SPOILER WARNING: This article contains major spoilers for "The Flash Reborn," the Season 4 premiere of The Flash.
The Flash's Barry Allen has returned just in time for Season 4. In "The Flash Reborn," the season premiere, Team Flash put their heads together and devised a way to bring Barry back without inciting the wrath of the Speed Force.
Cisco is the one to suggest bringing Barry back. He reveals that he has been working on a way to do so since the night Barry left and even consulted Earth-2's Harry Wells, Tina McGee of Mercury Labs, Team Flash alum Tracy Brand, Arrow's Felicity Smoak and Curtis "Mr. Terrific" Holt. With their help, he thinks he has devised a way to stabilize the Speed Force prison and free Barry at the same time.
Though Iris -- in her grief -- shuts Cisco down, he forges ahead anyway. He even goes so far as to track down Caitlin Snow, who has taken up as a bartender in order to find herself. Cisco convinces her to come help him, thus reuniting the old S.T.A.R. Labs team. Working through the night, Cisco and Caitlin made some modifications to the Speed Force bazooka. Specifically, they developed the "quarksphere," a round red ball filled with Barry's DNA and programmed to track him down using the electrical current of the Speed Force. The quarksphere is designed to take his place in the prison, tricking the Speed Force into believing Barry is still there.
Cisco fires the Speed Force bazooka at the quarksphere, but nothing appears to happen and Caitlin's system reports that the experiment has failed. However, that turns out to be false, as Barry is pulled from the Speed Force and hits the ground running -- in Ivy City, some 300 miles away from where they made the attempt.
Fortunately, some state troopers picked Barry up and one of the cops from Keystone recognized him, so they shipped him back to Central City. Less fortunately, Barry was found in a bad way, rambling off what appears to be nonsense and scrawling symbols across any surface he encounters. He remains in this state for nearly the rest of the episode, until Iris intentionally puts herself in harm's way in the hopes that it will make him snap out of it. This does the trick, and Barry returns to his normal self before the credits roll.
Starring Grant Gustin as the Scarlet Speedster, The Flash airs Tuesdays at 8 p.m. ET/PT on The CW. The series also stars Jesse L. Martin, Tom Cavanagh, Carlos Valdes, Candice Patton, Danielle Panabaker, Keiynan Lonsdale and more.