Barry has his hands full when he takes on a dangerous meta who can control technology, while also confronting an obstacle in his personal life: the ramifications of abandoning Iris for six months to balance the Speed Force. Meanwhile, Gypsy breaches in for a hot date with Cisco, but she gets annoyed when his work keeps them apart.

When collectors of Native American artifacts are attacked by a meta named Mina Chayton who can bring inanimate objects to life, Barry turns to a surprising ally for help. Determined to crack the identity of The Thinker, Harry enlists Cisco's help to summon the ultimate think tank: "The Council of Wells'," a roundtable of the brightest Harrison Wells' from various Earths.

A meta who can shrink anything he touches battles Team Flash. Cisco and Ralph get caught in his crossfire and are shrunk to miniature versions of themselves. Cecile realizes her pregnancy has caused her to have temporary powers and discovers she can hear other people’s thoughts, which unnerves Joe. Meanwhile, Barry meets someone with a mysterious connection to Henry Allen.

When Barry needs help transporting a dangerous meta, he calls on a new friend for help - Leo Snart AKA Citizen Cold. Meanwhile, Cisco becomes suspicious of Harry.

When DeVoe assaults an A.R.G.U.S. facility to complete his Enlightenment Machine, Barry realizes the only way he can stop him is if he allows Cisco and Caitlin to accompany him into the facility. Still shaken by Ralph’s death, Barry isn’t sure he wants to risk any more of his friends’ lives and considers taking on DeVoe solo.