Whilst nursing The Hangover from Hell, Ellen stumbles downstairs to discover the kitchen slowly filling with water. Panic quickly sets in, and the three flatmates find themselves in the attic desperately attempting to switch off the water supply. But when Ben, Alexa's Hinge date from the night before, walks in, the door slams, the handle breaks, and all four of them are trapped. As the long hours tick by, Ellen nurses her sore head whilst Ben and Alexa really get to know each other, and Jack plans an unorthodox rescue mission. But soon Ellen wonders if Ben really is a stranger after all. She is sure she knows him from somewhere . . . Will these housemates ever get out of this attic? Will they survive the wrath of Elias The Evil Landlord? And will Jack please stop live-tweeting this whole fiasco? Welcome to The Lock In.