“The Flash” star Grant Gustin explained why Barry and his team enlist the help of their former foe Amunet in tonight’s Season 4, episode 21 of the CW series.

In a recent interview with Entertainment Weekly, Gustin said that Team Flash is forced to rely on Amunet (Katee Sackhoff) because they’re already running out of options to stop The Thinker (Neil Sandilands) from reducing humanity to a simplified state.

“It’s just an example of Barry (Gustin) being in desperation mode,” Gustin said. “I think anything that we can try that we haven’t tried, Barry is willing to try. We’re talking about the end of all of humanity as we know it.”

Because of DeVoe’s tech powers courtesy of Kilgore (Dominic Burgess), Team Flash needs “some kind of weapon that has no tech involved, and Amunet fits that perfectly,” Gustin said. “Iris [points out] that Barry’s always fought for every citizen in the city, because he knows that ultimately there’s good at the core of everybody, including Amunet.”

As revealed in the trailer for the episode, Caitlin (Danielle Panabaker) is the one who tells the team to consider reaching out to Amunet for help. Though Barry, Joe (Jesse L. Martin) and Iris (Candice Patton) say that Amunet isn’t to be trusted, the whole team eventually agrees to recruit her after Caitlin points out that Amunet is immune to DeVoe’s powers.

Elsewhere in the episode, Harry (Tom Cavanagh) hits an all-time low when the Council of Wells kicks him out of the group after they find out that he’s losing his intelligence. Harry’s dismissal pushes Cisco (Carlos Valdes) to assemble a new group of Wells, which he dubs as the Council of Harrisons.

Though Harry is disappointed to know that some members of the Council of Harrisons are actually ex-members of the Council of Wells, executive producer Todd Helbing revealed to TVLine that the Council of Harrisons actually has something good to offer.

Helbing explained that whereas the Council of Wells was “all about intelligence and being the smartest people in the universe,” the Council of Harrisons is “an emo version” of the council that teaches “Harry that there’s emotional intelligence that perhaps he should tap into.”

“The Flash” Season 4, episode 21, aptly titled “Harry and the Harrisons,” airs on Tuesday, May 8 at 8 p.m. EDT on The CW.

Katee Sackhoff as Amunet
Barry’s desperation to defeat The Thinker (Neil Sandilands) forces him to team up with Amunet (Katee Sackhoff) in Season 4, episode 21 of CW’s “The Flash.” The CW