Oliver, Arsenal, and Diggle track down the location of aboomerang-wielding killer named Digger Harkness but aresurprised when they come face to face with an A.R.G.U.S. team.Diggle asks Lyla why A.R.G.U.S. is involved but she defersuntil Harkness attacks the building, killing several agentsand targeting Lyla. The Arrow joins the fight and gets helpfrom an old friend--the Flash. Harkness manages to get away andOliver teams up with Barry again to find him before he can getto Lyla. When Harkness plants five bombs in the city that aretimed to explode at the same time, both teams must cometogether to save the city.
