Melissa Benoist as Supergirl, Chris Wood as Mon-El
Mon-El (Chris Wood) starts teaching Kara (Melissa Benoist) some fight techniques they could use against the Worldkillers in Season 3, episode 15 of CW’s “Supergirl.” The CW

Kara undergoes training under Mon-El’s tutelage in the next episode of “Supergirl.”

According to the synopsis for Season 3, episode 15 of the CW series, Mon-El (Chris Wood) begins training Kara (Melissa Benoist) in fighting techniques he’s learned in the future for battling Worldkillers.

As Mon-El revealed to Kara towards the end of the last episode, the Legion didn’t land on National City by accident. While Mon-El confirmed that they did hit a disruption, he said that Brainiac 5 (Jesse Rath) and Imra (Amy Jackson) hit it intentionally. The Prince of Daxam went on to share that his Legion team members hid the real mission to him because they didn’t trust that he’d want to come back to Kara’s time.

When asked what the Legion’s real mission is, Mon-El said that they are there to locate Pestilence, the third Worldkiller that Supergirl and the D.E.O. haven’t found yet. “In 1000 years she evolves into Blight,” Mon-El told Kara. “So if we can find her now, in this time, then we can save everyone, today and in the future.”

After Kara pointed out their common enemy has been the Legion’s enemy for years, Mon-El offered to teachher fight techniques, including “cape tricks,” which they could use against the Worldkillers.

Elsewhere in the episode, Myr’nn (Carl Lumbly) inadvertently causes psychic disturbances at the D.E.O., leaving Supergirl and J’onn (David Harewood) containing the resulting chaos. While the origin of the psychic disturbance is unclear, it might be connected to dementia Myr’nn is currently struggling with.

“I personally have a dad who has Alzheimer’s right now, so it’s very personal; I start crying in the editing room all the time,” “Supergirl” co-showrunner Jessica Queller told TVLine of writing the arc about Myr’nn and J’onn. “It’s a very personal story to me and to a lot of other people, and so we’re really trying to execute M’yrnn’s deterioration of his mind in an authentic, universal way and show how it impacts the father and son. However, we’re then adding a Martian dimension to that, where Martians are able to share memories and thoughts in a psychic way, so there’s going to be a component in which J’onn has the opportunity to take on all of M’yrnn’s memories and history. How that will impact J’onn and who he is [leads to] a very exciting twist in the finale that I think everyone will be excited and should stay tuned for.”

“Supergirl” Season 3, episode 15, titled “In Search of Lost Time,” airs Monday, April 23 at 8 p.m. EDT on The CW. Watch the trailer for the episode below: