Jenna (Scout Taylor-Compton) gets into a car accident with her boyfriend, Jamie, who eventually dies. Three years later, while coping with her past tragedy, Jenna is invited to stay for the weekend in a lakeside cabin by her best friend Renee (Christina Ulloa). They are joined by Reneeâs irresponsible boyfriend, Michael (Michael Copon), and his friend, Ian (Travis Van Winkle), and sail off at Ian's uncle, Wade's (Tyler Mane) lakeside cabin. They are greeted by Wade along with his friendly dog, named Beau. They settle in the cabin and plan on attending a party, since there is a festival happening around the nearby town at night. Jenna goes to her room and refuses to take her pills so she could have fun with her friends. While they all eat dinner, Wade mentions how he may not be around while they are away since he has work to do. The group gets fascinated when they stumble inside a sauna Wade built. While they enjoy spending time inside, the temperature gets warmer and they decide to swim at the lake. Trembling in cold, they all head back inside the sauna. Meanwhile, Michael gets high from the marijuana Wade had given to him, where Renee rebuffs his sexual advances. This upsets Michael and gets out of the sauna. As the temperature continues to rise, Renee ultimately decides to leave but the door is blocked from the outside. The trio think it is just one of Michael's pranks since they all know he's mad at Renee, which they don't find amusing. They soon realize that they are trapped in the sauna and attempts to break a small window on the door, injuring Ian's hand. They all take turns gasping for air as the temperature raises even higher with another unsuccessful attempt to unblock the door from the outside. The group then finds a hidden controller which they all can't risk destroying, since Ian believes it would just alter the temperature.Meanwhile, Wade is seen handling the fireworks for the festival with another guy, when Beau tracks the trio's scream, begging for help, from the back of the house. Michael shows up at Wade's and both disregard Beau's barking. Michael clearly thinks the three left him and attended the party, since he couldn't help himself from getting high. The two hang out and start a conversation as Michael explains that he wasn't permitted to catch up at the party with the group since he didn't have a ticket and returned home.Back at the sauna, the situation escalates as the group runs out of water to drink and Renee gets sick from the temperature. Renee ultimately decides to break the controller, thinking it would lower down the temperature, but is stopped by Jenna who inadvertently strikes her head, leaving her unconscious. Jenna starts freaking out and decides to break the controller herself, which does in fact increase the heat as Ian feared. Ian becomes hysterical and burns himself badly in an attempt to prevent the steamer from heating the room out of control. He fails and the steamer blows up, killing him. The explosion frees the door and Jenna steps out in shock and wanders the house before reality snaps her back from unconsciousness to the floor of the sauna. She finds Renee alive and lets her near the window to breathe.Michael returns to the cabin where flashbacks shows him absentmindedly knocking over wooden steps and setting them against the door. It is revealed that the steps fall into place against a raised floor by the occupants as they talk and move the door themselves. Meanwhile, Wade arrives at the cabin and discovers the two girls, alive and calls the paramedics who take Jenna and Renee away on stretchers as they hold hands.
Output: Question: What does Renee break?, Answer: The temperature controller