Oliver, Canary, Diggle and Felicity return to the lair and find Slade waiting for them. An epic battle breaks out and one member of Team Arrow is sent to the hospital. Thea hits her breaking point, but just as Oliver is about to reach her, Slade intervenes and Oliver is faced with a choice – his battle with Slade or his family. Meanwhile, Laurel struggles with a new secret.
Clarke’s newfound romance with Finn is threatened. Octavia suffers a blow to the head and wakes up to find a Grounder watching her. On the Ark, Abby exposes Kane’s plan to reduce the population of the Ark. Jaha and Abby notice a signal and realize at least some of the 100 must still be alive on Earth.
Philip and Elizabeth both find themselves faced with painful turns in their various missions. Stan fights to gain access to an American military program that could give him the upper hand in his battle of wills with Oleg.