Arrow 5x22 spoilers
Black Siren (Katie Cassidy) returns in “Arrow” Season 5, episode 22. The CW

Oliver had a pretty anti-climactic showdown with Prometheus in the last episode of “Arrow” Season 5, which should have been the first hint that their fight isn’t over. The episode 22 synopsis reveals that Chase will get some help from friends.

In episode 21, Prometheus (Josh Segarra) learned that his father was trying to disown him. The devastating news led to Chase putting down his weapons and forfeiting the fight. He was ready for Oliver (Stephen Amell) to kill him, but the Green Arrow tried to do the right thing and locked him up instead. He might regret that choice in episode 22.

“Black Siren returns to help Chase,” the synopsis for the CW drama teases. It’s always difficult for the characters to see Black Siren (Katie Cassidy). After all, she looks just like Laurel.

READ: “Arrow” finale will include “double whammy” for Oliver

She is part of Prometheus’ big plan, which makes it seem like Chase may have known Oliver was going to lock him up. “Chase knows exactly what he’s doing, and he understands how unsettling seeing somebody that looks like Laurel Lance is going to be for the rest of the team,” co-showrunner Wendy Mericle told TVLine. She also revealed that Black Siren and the new Black Canary (Juliana Harkavy) will face off.

Before the ladies battle, however, the team will be under the impression that they can celebrate. It’s perfect timing too. “Felicity (Emily Bett Rickards) organizes a birthday party for Oliver,” the synopsis reveals. It’s been years since Oliver Queen went to a party just for fun. But will he actually get to attend or will Chase ruin the festivities?

Judging by the promo video, it looks like the latter. After Oliver reacts poorly to a surprise party, Chase starts to mess with Team Arrow through his friends on the outside. “He’s picking us off one by one,” Ollie says. Is that why the title of “Arrow” Season 5, episode 22 is “Missing”?

Watch the promo video below:

Elsewhere, some of Team Arrow has to worry about non-superhero activities. Lance (Paul Blackthorne) has been pushing Wild Dog (Rick Gonzalez) to do the right thing, but Rene isn’t so sure he is the best influence on his little girl. He skipped his custody hearing and lost his chance to get his daughter back. “Lance is furious after Rene misses the custody hearing for his daughter,” the synopsis notes.

Lance’s mood will only get worse when he finds out Black Siren is back. After all, his own daughters are the reason he is so invested in Rene’s father-daughter relationship. He looks seriously discomforted in the photo of their confrontation below.

Black Siren might not be the only villain to worry about. In the finale, Chase is assembling an army of femme fatales. Black Siren, Evelyn Sharp (Madison McLaughlin) and Talia al Ghul (Lexa Doig) will all be there to help Prometheus take on the Green Arrow. Meanwhile, Oliver will be assembling his own new team: Deathstroke (Manu Bennett), Nyssa (Katrina Law), Merlyn (John Barrowman) and Digger Harkness (Nick. E. Tarabay). Fans will have to tune in to see if these teams start coming together in the penultimate episode of the season.

“Arrow” Season 5, episode 22 airs Wednesday at 9 p.m. EDT on The CW.

Arrow 5x22 Black Siren
Black Siren (Katie Cassidy) confronts Lance (Paul Blackthorne) in “Arrow” Season 5, episode 22. The CW
Arrow Oliver's birthday
Team Arrow gathers for a birthday party in “Arrow” Season 5, episode 22. The CW
Arrow 522 Olicity
Felicity (Emily Bett Rickards) plans a surprise party for Oliver (Stephen Amell) in “Arrow” Season 5, episode 22. The CW
Arrow Merlyn
Malcolm Merlyn (John Barrowman) appears in “Arrow” Season 5, episode 22. The CW