In this episode of Flash, Barry and Joe are questioning Clifford and his wife, Marlize. Based on this first meeting and Team Flash's deep dive into their background, the DeVoes seem like a perfectly normal married couple.
Four years ago, Clifford was simply a history professor at Central City University who was passionate about enlightening young minds but was failing at it because his students were uninterested. Marlize shared his passion. Clifford figured he couldn’t implement his ideas about teaching because his mind was too small, so he designed the thinking cap, which would grant him access to his brain’s unlimited power. He asked his wife, a brilliant scientist and engineer in her own right, to build it.
Marlize built the thinking cap, but there was one small problem: They didn’t have an energy source large enough to power it. So, on the night the accelerator was set to be turned on, Clifford stood outside of S.T.A.R. Labs in the rain wearing the cap. His head got struck by lightning caused by the particle accelerator. When he regained consciousness, he had achieved enlightenment and was the smartest man in the world.
With these new powers, Clifford believes he can finally achieve his goals. Unfortunately, his super intelligence comes with a side effect: His brain is sapping energy from his body, causing muscle degeneration and paralysis. Unlike most metas, he wants to use these gifts for good, but he can’t because it’s killing him.
Even after Team Flash learns everything there is to know about Clifford, Barry remains certain that he’s the guy both Savitar and Abra Kadabra warned him about. So he decides to take matters into his own hands.
Barry drops by Clifford’s class one day to ask him more questions. This doesn’t go anywhere, so he steals Clifford’s mug and tests it. The tests come up negative, and Barry gets in even hotter water when Clifford and Marlize complain to Singh about Barry’s harassment. Singh orders Barry to stay away from Clifford — but that doesn’t stop Barry’s obsession. Barry starts his own stringboard to support his investigation. His growing obsession worries Iris, who keeps reminding him that they’re getting married in seven days.
Barry discovers the camera inside the Samuroid head and decides to break into DeVoe’s home to investigate. DeVoes catches Barry on camera and reports it to Singh, who suspends Barry for two weeks.
Iris confronts Barry again, and he comes clean about what’s driving him so crazy. He’s been so happy since he returned from the Speed Force but he’s worried about losing this feeling.
Barry decides to confront Clifford once again. Clifford was expecting this, but this time he doesn’t pretend be a mild-mannered professor. Instead, he comes clean, he knows Barry is the Flash. He’s playing an elaborate chess game with Team Flash.
In the end, Barry shares what he learned with the team, leading Cisco to name Clifford the Thinker. Marlize asks Clifford why he’s willing to let Barry’s marriage go forward, and Clifford has a simple answer: “What is knowledge without love?”