We’ve less than a week before DC’s alien Dominators begin the four-part “Invasion” of Supergirl, Flash, Arrow and Legends of Tomorrow, but given at least half of The CW’s DC dramas traffic in time-travel, the invasion may already have begun. Like, World War II-begun. See for yourself, in a cryptic “found footage” teaser.

The CW released an eyebrow-raising new sneak peek of the four-night crossover under a Legends of Tomorrow banner, despite the DC teamup series acting as conclusion to the four-part event. In it, we see what appears to be the Dominators overtaking a World War II battlefield, but does that mean the Legends will be taking everyone back in time?

At the very least (and be wary of spoilers), here’s how Legends describes its leg of the “Invasion!” event:

ALL FOR ONE AND ONE FOR ALL IN THIS CROSSOVER OF SUPERHEROES — After learning the Dominators’ plan for the world, the Legends must work together with The Flash (guest star Grant Gustin), Supergirl (guest star Melissa Benoist) and Green Arrow (guest star Stephen Amell) to kill them once and for all. Meanwhile, Stein (Victor Garber) figures out, with the help of others, how the team can terminate the Dominators, but is distracted by the aberration he realizes he created in 1987.

It’s certainly possible that the Legends’ plan might involve a trip to the past (perhaps recruiting the JSA, while we’re at it?), but in the meantime, check out the real crossover trailer below, and stay tuned for Supergirl to kick off the four-night event with Monday’s “Medusa.”