SupergirlThe Flash, and Arrow are all back this week! Kara’s (Melissa Benoist) about to face the wrath of Mon-El’s (Chris Wood) mother, Barry (Grant Gustin) now has to deal with Killer Frost (Danielle Panabaker) as well as Savitar (Tobin Bell), and Oliver’s (Stephen Amell) war with Prometheus (Josh Segarra) is coming to a climax. Things are certainly heating up. Here are the synopses for the antepenultimate episodes of the 2016/17 seasons.

James’ (Mehcad Brooks) status as a hero is put to the test when he is forced to take on an alien alone. Guardian will prove his worth in ‘City of Lost Children’, directed by Ben Bray and written by Gabriel Llanas and Anna Musky-Goldwyn with story by Robert Rovner.

“THIS IS US” STAR LONNIE CHAVIS GUEST STARS – When an alien attacks National City, Supergirl (Melissa Benoist) and the DEO learn the alien is a Phorian, an otherwise peaceful race with telekinetic powers. Guardian (Mehcad Brooks) gets a lead on the Phorian’s address but instead of finding the culprit, he finds a very scared boy named Marcus (guest star Lonnie Chavis). Marcus will only trust James so it is up to Guardian to stop the attacks on the city. Rhea’s (Teri Hatcher) plan escalates.

Barry is willing to do whatever it takes to stop Savitar. Team Flash might finally come out ahead in ‘Cause and Effect’, directed by David McWhirter and written by Judalina Neira and Lauren Certo.

Photo Gallery & Extended Trailer for 'The Flash' Season 4 Premiere

DRASTIC TIMES CALL FOR DRASTIC MEASURES – Barry (Grant Gustin) takes drastic measures to stop Savitar. Meanwhile, H.R. (Tom Cavanagh) continues to push Tracy Brand (guest star Anne Dudek) to design the trap for Savitar and Killer Frost (Danielle Panabaker) returns with an interesting proposal.

Oliver’s fight with Prometheus is far from over. Mayor Queen will have a tough day in office in ‘Honor Thy Fathers’, directed by Laura Belsey and written by Marc Guggenheim and Sarah Tarkoff.

CHASE CONTINUES TO TORMENT OLIVER — Oliver (Stephen Amell) returns to the mayor’s office and faces one of his most pressing issues yet – the forced release of dozens of violent criminals prosecuted by Adrian Chase (Josh Segarra). Meanwhile, a crate is delivered to Oliver’s office containing a mysterious corpse encased in concrete.

Supergirl returns with ‘Ace Reporter’ todayThe Flash returns with ‘The Once and Future Flash’ tomorrow, and Arrow returns with ‘Dangerous Liaisons’ on April 26th all at 8/7c on The CW.