Flash fans be warned - Barry's timeline is about to get a little convoluted.

"Trajectory" dropped some major Zoom (Teddy Sears) teasers courtesy of Vibe (Carlos Valdes) and Velocity 9, but unfortunately, the March 22 episode was missing one major plot point. The Scarlet Speedster (Grant Gustin) will head to another alternate reality during Monday's Supergirl, and we're still wondering exactly how he'll get there. As it turns out, Barry's little trip through the multiverse won't happen until the end of episode 17, which will air the day after the highly-anticipated CW/CBS cross over.

"[The episodes] kind of flip order," executive producer Greg Berlanti said of "Flash Back" and "Worlds Finest," according to TV Line. "We're much better at coordinating the viewing patterns when we're crossing over on the same network. But when [it's folded into The Flash], people will get it."

In other words, die-hard Flash fans might want to DVR Monday's Supergirl outing and save it for 9 p.m. on Tuesday. By that time, Barry will have completed his seriously ill-advised trip to back to season 1 Central City and will have presumably found a way to travel through the breaches to someplace other than Earth-2. We're not exactly sure which parallel universe Kara Danvers (Melissa Benoist) lives in, but it certainly isn't the sepia-toned world of Zoom and Jay.

While visiting National City, Barry unfortunately won't have a chance to run into any STAR Labs doppelgangers. That's not to say iterations of Cisco, Caitlin (Danielle Panabaker), Wells (Tom Cavanagh), Joe (Jesee L. Martin), and Co. aren't walking Kara's world. Now that season 2 of Supergirl is definite, members of The Flash, Arrow, and Legends of Tomorrow family could crop up in various forms.

"We just talked about that recently," Berlanti told Entertainment Weekly. "There is room [for that], absolutely."

In the meantime, you can see Barry meet Kara during Monday's "Worlds Finest" and watch Barry give both Earth-1 and Earth-2 Wells an aneurism when he puts his timeline at risk in this Tuesday's "Flash Back."

Supergirl airs Mondays at 8 p.m. ET on CBS. The Flash airs Tuesdays at 8 p.m. ET on The CW.