The CW has announced the air date for “Supergirl” Season 2 finale.

According to TVLine, episode 22 of the Melissa Benoist-led series will air on Monday, May 22 at 8 p.m. EDT.

Plot details about the finale are being kept under wraps, but it was revealed last week that both Superman (Tyler Hoechlin) and Cat Grant (Calista Flockhart) are appearing in the season ender.

READ: Was Mark Gibbon Cast as Superman villain General Zod on “Supergirl”?

Hoechlin made his debut as the Man of Steel in “Supergirl” Season 2 premiere, where he helped his cousin Kara (Benoist) save Lena Luthor (Katie McGrath) from an assassination attempt. He stuck around for Season 2, episode 2, where he fought the classic Superman villain, Metallo (Frederick Schmidt).

Like the Man of Steel, Cat was also last seen in Season 2, episode 2. In that episode, she decided to take a leave of absence from CatCo Worldwide Media to find bigger and better things to accomplish after she felt stagnant in the world of media she already dominated. Before she left CatCo, Cat promoted James Olsen (Mehcad Brooks) to be her stand-in while she’s away.

Executive producer Andrew Kreisberg also revealed to Entertainment Weekly in February that the content of the box — which Lillian Luthor (Brenda Strong) found among Lex Luthor’s weapons in the Cadmus bunker, in Season 1, episode 12 — will be revealed.

“Supergirl” returns from its month-long hiatus with Season 2, episode 18 on Monday, April 24 at 8 p.m. EDT on The CW. According to the synopsis for the episode, Lena’s former boyfriend Jack Spheer (Rahul Kohli) comes to National City to introduce his newest breakthrough in nano-technology. To show her support, Lena attends Jack’s conference with Kara. But when Kara sees Snapper (Ian Gomez) at the event, she decides to tap into her reporter skills and question Jack about his invention.

Melissa Benoist as Supergirl “Supergirl” Season 2 finale, episode 22, is slated to air on the second to the last Monday of May. Photo: The CW