The Bubblegum Gang are a street gang who are hungry for bubblegum.
College students Paxton and Josh are traveling across Europe with their Icelandic friend Óli. After being thrown out of a club and visiting prostitutes in a brothel, the three return to their hostel to find there's a curfew and they've been locked out. A man named Alexi in a nearby apartment invites them in for the night. He convinces them to visit a Hostel in Slovakia filled with beautiful women who love American men, redirecting them from their original route to Barcelona.
The three board a train to Slovakia, encountering a strange Dutch businessman who touches Josh's leg. Josh yells at him causing the embarrassed businessman to leave. When they arrive in Slovakia, they are impressed the beauty of the town and the grandeur of the hostel, there, they are greeted by their roommates, Natalya and Svetlana, two beautiful women who invite them to the spa, and later to the disco. That night, at the disco Josh goes outside and encounters a group of street boys known as the "Bubblegum Gang" who demand money. They are about to attack Josh when the Dutch Businessman saves him. In return, Josh buys the Dutch Businessman a drink and apologizes to him for his reaction back on the train. Later, Paxton and Josh have sex and sleep with Natalya and Svetlana, while Óli sleeps with the desk girl. The next morning, they are surprised to see that Óli hasn't returned yet, and they are unable to contact him. They are approached by a Japanese girl named Kana, who shows them a photo of Óli and her friend Yuki, who is missing as well.
Later, after Paxton and Kana were fleeing in a car from the factory, Paxton spots Natalya, Svetlana, and Alexi. He runs them over, killing them. Paxton gives the Bubblegum Gang a bag containing bubble gum to let him pass and they later kill the two guards chasing them.
Shortly after the events of Hostel, Paxton is suffering from nightmares and lives in seclusion back in the US with his girlfriend Stephanie. The two get into an argument where Stephanie announces Paxton's paranoia as insufferable and exaggerated. She wakes up the next morning to find Paxton decapitated. An unmarked box (presumably containing Paxton's severed head) is then delivered to Elite Hunting boss Sasha (Milan Kňažko), as he relaxes at an outdoor cafe with his Bloodhounds.
In Italy, three art students, wealthy Beth , tough Whitney, and outcast Lorna are convinced by Axelle, a nude model they are sketching, to join her on a vacation to a luxurious spa, rather than Prague. The four travel by to a small Slovakian village and check into the local hostel, where the desk clerk uploads their passport photos to an auction website where people can bid all over the world to torture their victims. American businessman Todd submits the winning bids on Whitney and Beth for himself and his passive best friend Stuart.
Later that night, at the village's Harvest Festival, Lorna discovers that Beth has inherited a vast fortune from her mother. After Stuart and Todd receive their Elite Hunting tattoos, they go to the festival. Stuart approaches Beth and the two share a friendly, albeit awkward, conversation. Despite being warned about her safety from Beth, an intoxicated Lorna leaves to go on a boat ride with Roman, a charismatic local, who proceeds to kidnap Lorna with the help of two accomplices. Beth and Whitney leave the party, while Axelle volunteers to stay behind and wait for Lorna. Whitney wants to sleep with local Miroslav, but Beth convinces her otherwise, stating that Miroslav is too "shady" and promises to make it up to her.
The next morning Beth, Whitney, Axelle, and Miroslav head to the local spa to relax. Basking in the relaxing atmosphere of the hot springs, Beth is able to doze off. Meanwhile, the now naked and gagged Lorna is hung upside down, her feet are chained tightly together above her, and her wrists are chained tightly together behind her back. The men who kidnapped Lorna prepare the room with candles for a client named Mrs. Bathory who enters the room, strips off her robe, and lies naked beneath Lorna. She then uses a long scythe to repeatedly slash the screaming Lorna's back and torso, and revels in bathing in Lorna's blood, before fatally slashing Lorna's throat with a sickle.
Beth wakes up only to find herself alone and her belongings stolen. As she looks for her friends, she notices several men approaching her. Fearing for her life, she climbs over the spa walls. While making her escape, she is ambushed by the "Bubblegum Gang", a gang of violent street children. Before they are able to descend upon her, however, Axelle and Sasha appear and ward them away from her. Axelle escorts a flustered but somewhat relieved Beth to their vehicle. With Axelle and Beth away, Sasha confronts the children. Angry that they attacked Beth, Sasha draws out his gun and has one of the children, a boy, brought forward before him. He then kills the boy, and the rest of the gang flees.
Meanwhile, Whitney is taken out of her cell where many other people are restrained and soon to be tortured. Whitney is taken to a room where an old woman applies makeup to her bruised face. In an effort to calm Whitney down, who is screaming and pleading, the old woman unlocks one of Whitney's handcuffs. Whitney then bites off part of the old woman's nose and tries to escape, but is unable to escape due to the increased security since Paxton's escape. After being taken to Sasha's mansion, Beth realizes that Sasha and Axelle are responsible for Whitney and Lorna's disappearances after seeing the men who tried to kidnap her at the spa coming up the stairs of Sasha's home. She tries to hide and discovers a room filled with severed heads, including Paxton's, before being captured and taken to the factory. Having been notified via pager, Todd and Stuart are chauffeured to the factory, where they joke around with some of the tools and uniforms. Stuart then enters his room where Beth is strapped to a chair with a sack covering her head. Stuart looks around the room at the tools with horror. He then takes the sack off Beth's head and explains about Elite Hunting. Stuart tells Beth that the group is a worldwide secret society where members come to Slovakia to kill people that the organization abducts. He then unties her from the chair and almost decides to let her escape, but then knocks her out and reties her to the chair. The passive Stuart now suddenly becomes angry; ranting and raving at Beth as if he is talking to his domineering wife.
Whitney is taken to Todd's cell and strapped to a chair, where he gleefully terrorizes her with a circular saw but loses his nerve after accidentally cutting through part of her skull. Horrified by what he has done, Todd tries to leave without killing Whitney but one of the guards reminds him that he is contractually obligated to kill her and cannot leave until he does so. Todd angrily refuses, prompting the other guards to turn some savage dogs loose and maul him to death. The Elite Hunting representatives try to find someone to finish off Whitney, inquiring whether an Italian man who is shown to be eating Miroslav alive and a man who has his victim chained to an electrified metal bed are interested.
Stuart, now torturing Beth, is approached by The Elite Hunting representatives. They offer Whitney to Stuart. After discovering that Todd has been killed, the now deranged and sadistic Stuart accepts the offer and kills Whitney by beheading her. He returns to Beth, blaming her for Todd's death. As he resumes torturing her, she seduces him into releasing her from the chair. Stuart lays Beth on the floor and begins to attempt to rape her, but she fights him off as he lies on her and chains him to the chair. Beth demands that Stuart tell her the code to the cell door, then sticks a needle in his ear when he refuses to tell her. Stuart tells Beth the code (which is Beth's birthday, December 12), but she still needs to be buzzed through the door, which inadvertently summons Sasha and the guards to the room. Beth offers to buy her freedom with part of her inheritance. When Sasha explains to her that she must kill somebody to leave, Stuart insults Beth with a slur she hates being called. Although warned, he proceeds to call her it again. Enraged, Beth cuts off Stuart's genitals and tosses them to one of the guard dogs, leaving him to bleed to death as he screams in agonizing pain. Per the standard contract, Beth is given an Elite Hunting tattoo and is made a member.
In the closing sequence, Axelle is lured from the village festival into the woods by the Bubblegum Gang, who stole her purse. The revenge-seeking Beth surprises and beheads her for leading her friends to their deaths. The Bubblegum Gang then play soccer with Axelle's head.
A young man, named Travis, going into a hotel room where a Ukrainian couple, Victor and Anka, are currently staying. The couple offers Travis some Vodka, but he declines, saying that he brought beer for everyone. The three have a beer and Anka goes off to take a shower. Victor goes off to ask her a question when he finds her unconscious. Victor then calls for Travis's help. Travis walks in nonchalantly, and just stares at the couple, and Victor passes out from being drugged by the beer Travis gave him. It is then revealed that Travis is a member of the Elite Hunting Club. Victor later wakes up in a cell in an abandoned building. Two guards walk in and drag Anka out of her cell.
Scott and his fiancé Amy are out in front of their home, and Carter, Scott's friend, pulls up. The three chat for a while and Scott leaves Amy to go with Carter to Las Vegas for Scott's bachelor party. Once in Las Vegas, Scott and Carter meet up with Mike and Justin, two of their friends. The four go to a nightclub, where they end up meeting Kendra and Nikki, two escorts Carter had secretly paid to have sex with Scott. Kendra and Nikki tell the four men about a "freaky" party they could go to. The four men take a cab to an abandoned building. Confused, the men knock on the door and are invited in by a bouncer. Once at the party, Kendra makes a move on Scott, but he denies her, and tells her about how he was previously unfaithful with Amy and almost lost her, and that he does not want it to happen again. Mike and Nikki walk in and kick out Kendra and Scott. Scott wanders outside the building and the cabbie finds him drunk, pounding on the door to get back into.
Scott wakes up in the morning in his hotel room with Carter and Justin. The three wonder where Mike is, and try calling his phone, but get his voice mail. They shake it off and assume he will show up later.
Meanwhile, Mike awakens in a cell, in an undisclosed location, and starts panicking. Two guards enter and take Mike away. They then tie him into a chair in the middle of an empty room. Curtains open revealing one wall is made of glass, and Mike is on display to be gambled upon by wealthy clients. A doctor enters the room, and Mike pleads with him, stating that he has a family. An announcement congratulates the gamblers who bet that he would plead for his life using his family. The doctor cuts Mike's face off, then leaves him as he screams and the curtain closes. The audience gives a round of applause for the show.
Worried that they have not heard from Mike, Scott, Carter, and Justin travel to Nikki's trailer. Scott and Carter break in while Justin waits outside. They look for Nikki and Mike, but they do not find anyone in the trailer. They hear a noise outside, and while checking it out, two people burst through the front door and throw Justin down. One of the people is Kendra. Kendra questions the three guys about why they broke into Nikki's, and they explain. She then reveals that Nikki is also missing.
Meanwhile, Nikki wakes up with a ball gag in her mouth and is dressed by Travis in a cheerleading outfit. She is brought into the same room as Mike and is strapped to a table. A doctor then sprays a sweet chemical in and around her mouth, and teases her with a cockroach as she screams. He then releases a jar full of cockroaches onto Nikki. The cockroaches crawl into her mouth and suffocate her to death.
After driving, Scott, Carter, Justin, and Kendra get a text message from "Mike" to meet him and Nikki in a hotel room. When they get there, everyone but Justin goes inside the room. When inside they get jumped by numerous men and are gassed, and put in the back of a van. Justin hears the van and gets out to investigate. He is then knocked out and put in the van by Travis. Scott, Carter, and Justin wake up in individual cells along with Victor. Kendra is still unconscious. The two guards take Justin away, and Carter calls the guard telling him that he is also a client and that it is his turn. Scott is shocked and does not know what to do.
Justin gets strapped into a chair and a mist settles in the room. Carter, Flemming, and Travis watch as a woman dressed as an alien shoot arrows into Justin's limbs. Shortly after, Scott gets taken into the room and is strapped into the chair. Carter comes in to the room, and Scott asks him why he is doing this. Carter reveals he wants Amy all for himself, as they were in a relationship before she ended up with Scott. He then says that once Scott dies, he will comfort Amy and she will want to be with him. He also says that Mike was just at the wrong place at the right time, while he genuinely feels sorry for Justin because he believes that Justin did not deserve to die. As Carter turns his back, Flemming orders Scott to be let go from the chair. Scott and Carter fight, and Scott ends up stabbing Carter multiple times. Scott then breaks out of the room and runs away. Victor ends up killing one of the guards and gets the keys and frees himself. He kills another guard, but the guard simultaneously shoots Victor in the chest, killing him. Scott calls the cops and frees Kendra. While running away, Kendra is shot by Travis. Scott and Travis fight, and Scott cuts his arm off and bludgeons Travis to death with Justin's crutch.
Flemming sets the building to explode and attempts to drive away, but Carter, who was hiding in the back seat, kills him and takes his car. The parking garage has spikes that will puncture the tires of a vehicle leaving, so Carter places Flemming in front of the spikes, then exits, driving Flemming's body onto the spikes so the car can escape. Carter drives away from the building, but he sees Scott in his rear-view mirror. Carter gets out and locks the front gate before Scott can get to him. Carter drives away while the building explodes with Scott still within the compound gates. Sometime later, Carter is comforting Amy, and she invites him to stay the night. He accepts. Amy goes to get a bottle of wine and when she returns, she tells Carter that Scott is still alive and stabs Carter in the hand with a corkscrew. A burned Scott comes behind Carter and drags him to the garage. Scott then kills Carter with an electric tiller.