SPOILER WARNING: This article contains major spoilers for “We Are the Flash,” the Season 4 finale of The Flash.

In The Flash's Season 4 finale, the team said goodbye to one of their own. In "We Are the Flash," Harry bid the team farewell and returned to his Earth to reunite with his daughter.

Over the course of Season 4, Harry struggled with the fact he wasn't as smart as Clifford DeVoe, aka the Thinker. Eventually, he arrived at the same epiphany DeVoe himself once did: he should create a device to enhance his intelligence. Harry set to work on it right away, dubbing it his Thinking Cap.

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However, Harry's Thinking Cap backfired on him. He overloaded his brain with dark matter, which caused him to start losing his intelligence. The harder he thought, the faster he lost his ability to do so. He began forgetting rudimentary elements of his day-to-day life, like conversations. By the finale, he was reduced to babbling.

Fortunately, Marlize DeVoe provided the team with a solution. She gave them the specs for a cap that was supposed to reverse the damage. When they put it on him, it did so -- at least, to an extent. He was able to communicate and function normally, but he had lost his super-intelligence and years of education.

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Team Flash was disappointed by the news, but Harry wasn't. He was simply excited to have another shot at life. As he described it to Cisco, he has now found the balance between his head and his heart. Realizing this, he gave the team a big hug and rushed off to Earth-2 to reunite with Jesse Quick, his daughter.

Despite this, Harry actor Tom Cavanagh will return for Season 5 -- but he'll be a different Wells this time. "I don’t want to tell you yet who he is, but when I was up there in Vancouver shooting for the finale, I talked to Tom for quite a bit about it. We landed on a pretty fun and interesting new Wells to join the team," executive producer Todd Helbing revealed to Entertainment Weekly.

Airing Tuesdays at 8 p.m. ET/PT on The CW, The Flash stars Grant Gustin as Barry Allen, Carlos Valdes as Cisco Ramon, Danielle Panabaker as Caitlin Snow, Candice Patton as Iris West, Jesse L. Martin as Joe West, and Tom Cavanagh as Harry Wells, with guest appearances from Keiynan Lonsdale as Wally West and Hartley Sawyer as the Elongated Man.