Ana Mercedes

Oliver must tackle a new threat when bombs start to go off in Starling City. Felicity discovers the person setting them off is Mark Sheffer (guest star Sean Maher), a man who goes by the nickname "Shrapnel." Arrow discovers Shrapnel's next target is Sebastian Blood's "Unity Rally" and tries to talk the alderman out of hosting it, but he refuses. Arrow sets off to stop the bombing, but Shrapnel tricks him and traps him in a bomb-laced antique store where he is unable to move without setting off the device.

Arrow teams up with Laurel to find the man in the mask. Conflicted after Laurel reaches out to the Arrow asking him to investigate Sebastian Blood, Oliver is unsure whether to believe her accusations against the man he has publicly supported for mayor, but decides to trust Laurel. However, when the pair gets too close to the truth, Sebastian exposes Laurel's drug addiction and has her arrested. Meanwhile, Roy reveals his new super-strength to Sin who wants to test out his abilities. Unfortunately, Roy isn't able to contain his rage once unleashed and almost kills a man. Back on the island, Oliver is surprised when Sara reveals a secret about Laurel.

Valens' past haunts him when a 1998 case involving a drug mule is reopened and he is the focal point.