A mad bomber is on the loose in the city and Arrow is determined to stop him. Felicity is out of town visiting a comatose Alan when it starts but returns to Starling City as soon as she hears what's happened. When his attempt to track and apprehend the bomber - who goes by the name Shrapnel - fails, he blames it all on a stunned Felicity. Laurel meanwhile has been seeing local politician Sebastian Blood but learns a dark secret from his past. Roy has some difficulty explaining his newfound strength to Thea. In a flashback to the island, Sarah, Oliver and Slade have to deal with Shado's death.