Oliver must tackle a new threat to the city when bombs start to go off in Starling City. Felicity discovers the person setting them off is Mark Sheffer, 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. While Felicity helps Oliver, Diggle races to the plaza to find the bomb before it goes off. Meanwhile, Roy continues to hide his new strength from Thea but, after she witnesses his super strength in action at the rally, she demands answers. Laurels suspicions about Sebastian grow stronger once she learns that he grew up with Cyrus Gold, the man who killed Lance’s partner. After Donner refuses to help her investigate, she turns to Arrow for help.
Elenco: Stephen Amell , David Ramsey , Katie Cassidy , Willa Holland , Paul Blackthorne , Emily Bett Rickards , Echo Kellum , Colton Haynes , Rick Gonzalez , Juliana Harkavy , John Barrowman , Susanna Thompson , Manu Bennett , Colin Donnell , Josh Segarra , Sea Shimooka , Ben Lewis , LaMonica Garrett , Katherine McNamara , Joseph David-Jones , Stephen Amell , Summer Glau , Susanna Thompson , Sussana Thompson , Willa Holland .