Arrow - Season 4 Episode 1 -

Oliver and Felicity’s blissful getaway is cut short when Thea and Laurel pay them a visit and tell Oliver they need his help back in Star City. The city has been attacked by “Ghosts,” assassins led by a dangerous man named Damien Darhk. However, when Oliver returns, Diggle makes it very clear that he doesn’t want Oliver on the team.