Krys Marshall

The team searches for a border-crossing serial killer who targets prostitutes and the homeless.

Marshall bequeaths a "slap bet" slap to Ted and Robin; Lily's estranged father (Chris Elliott) visits for Thanksgiving.

Hours after calling Gibbs about a possible case, a Marine is found dead in Quantico; McGee and Bishop pose as a married couple.

As Kevin stresses about the premiere of his play, he receives support from an unexpected source. Randall struggles under the pressure of both his work and ailing father. Rebecca and Jack's Valentine's Day doesn't go as planned.

Still reeling after learning about Lena's secret, Supergirl asks Guardian for a favor that could alter his relationship with Lena forever. Meanwhile, with all three Worldkillers united, Supergirl and the team brace for an epic battle.

The DEO captures a second Worldkiller, Purity (guest star KRYS MARSHALL). Supergirl and Alex use very different methods of interrogation with Purity in the hopes of finding out how to defeat Reign. However, Purity escapes and attacks the city's subway tunnels. Meanwhile, J'onn, Winn and Mon-El band together to fix the Legion ship.