Twilight's Last Gleaming

S1 E5: Clarke's newfound romance with Finn is threatened. After suffering a blow to the head, Octavia wakes up to find a Grounder watching her. On the Ark, Abby exposes Kane's plan to reduce the population of the Ark. Then, Chancellor Jaha and Abby notice a signal and realize at least some of the 100 must still be alive on Earth.