A park clean-up seems like a great chance to do some good in the Star City community and an ideal photo-op for mayoral candidate Oliver Queen (Stephen Amell). Of course, nothing is that simple on "Arrow," and in this clip from the midseason finale, "Dark Waters," a heavily armed helicopter ruins the civic-minded fun, with Oliver, Thea (Willa Holland), Laurel (Katie Cassidy) and Felicity (Emily Bett Rickards) all doing their best to shield civilians amid the chaos.

"Dark Waters," the midseason finale of "Arrow," airs 8 tonight on The CW. Here's the official description of the episode:

OLIVER TAKES ON HIVE - After the city is attacked again, Oliver (Stephen Amell) makes a bold move against HIVE. Malcolm (John Barrowman) checks in on Thea (Willa Holland) and leaves her with a warning. Things take a horrible turn when Damien Darhk (guest star Neal McDonough) retaliates in a brutal manner at Oliver's mayoral holiday party. John Behring directed the episode written by Wendy Mericle & Ben Sokolowski (#409).