SPOILER WARNING: The following article contains major spoilers for "Shogun," tonight's episode of "DC's Legends of Tomorrow."
It's hardly a surprise when another hero from the Arrowverse pops up on "DC's Legends of Tomorrow" -- after all, one of The CW's great strengths has been building a shared world -- but Barry Allen's cameo on tonight's episode was something a little different.
While the most of the team was off in feudal Japan, both halves of Firestorm were left to tend to the Waverider, where they found a secret armory. It became clear that Rip Hunter didn't want any of the Legends to know about it, although they're not sure why. Shortly afterwards, though, they find an audio transmission from the Flash, sent from 40 years in the future. The message itself was vague, only hinting that Barry's about to reveal something huge to Rip, before the scene cut away.
Though the camera cut away before the viewers got to hear the big reveal, Professor Stein and Jax know what it is by the end of the episode. Whatever the secret may be, it's huge, so much so that they have to keep it between themselves for the time being. Stay tuned for more on this in our full recap and review later tonight.
Airing Thursdays at 8 pm ET/PT on The CW, "DC's Legends of Tomorrow" stars Arthur Darvill as Rip Hunter, Brandon Routh as the Atom, Victor Garber and Franz Drameh as Firestorm, Caity Lotz as White Canary, Maisie Richardson-Seller as Vixen, Dominic Purcell as Heatwave and Nick Zano as Citizen Steel.