The Lightman Group are called in when Washington DC comes under terrorist threat; with national security at stake, Cal and co need to be on their A-game.
The International Response Team suspects an American girl is in danger, after being tricked by someone posing as her boyfriend and asking her to meet him in Turkey.
Locke, Sayid and Kate investigate a strange structure and its mysterious inhabitant; Sawyer competes in a pingpong competition to get back his belongings.
Jen and Greg hire Clementine as a part-time nanny for Lark; Tyler's new girlfriend turns out to be Sophia's fourth-grade teacher; John hires a company to set up an escape room in his house; Matt grows frustrated with Colleen.