A flashback features Clifford DeVoe as a teacher who struggles with his students. He shows Marlize his ideas for the thinking cap.
In the present, Barry and Joe continue to investigate Clifford after DeVoe's name came up in the cases for the bus-metas. Clifford only recognizes the Black Bison out of the bus-metas.
They return to Star Labs as Barry is still not willing to let DeVoe go. A flashback from four years ago of the night when the particle accelerator blew up shows Marlize having finished the design of the thinking cap.
Barry goes to one of Clifford's lectures as he asks where he was on January 7, four years ago. Barry steals Clifford's mug and brings it for scans at Star Labs. The team are not sure DeVoe is their guy.
Another flashback shows Clifford and Marlize attending Harrison's press conference of the particle accelerator launch. Later on, Clifford puts on the thinking cap as the accelerator goes off and thus reveals how he got his powers.
Barry gets summoned by Captain Singh as the DeVoes are reporting Barry's harassment of Clifford. They leave as Barry tries to explain to the captain that there is something not right about Clifford.
Iris goes to see Barry as he won't give up on the DeVoes being involved somehow with the bus-metas. A flashback shows Clifford's intelligence has grown a lot since the accident while also showing how he got paralyzed.
Barry discovers the camera hidden within the Samuroid helmet and runs over to their house to get more clues. A flashback shows a doctor breaking down the news to Clifford that the accident has made him very sick.
Barry returns to Star Labs and tells the team about the camera but also reveals that he broke into their home. Marlize reports Barry's crime to CCPD as she got security photos of him breaking into their home.
Iris has a talk with Barry after he gets suspended. In another flashback, Clifford's condition gets worse.
Barry goes to see Clifford to try one more time to find out the truth. Clifford outs himself as being responsible for the bus-metas as he has nothing to fear with Barry.
Barry tells the team that Clifford outed himself as they try to figure out how to stop him. Wally shows up to surprise the team.
Back in the Thinker's lair, Marlize helps Clifford get back in his other body.