Caitlin (Danielle Panabaker) goes to her mother to find out how her meta-human powers are developing. Meanwhile, Earth-19 Harrison Wells (Tom Cavanagh) has arrived in Earth-2, but there is something suspicious about him.

Previously in "The Flash," Caitlin has developed her doppleganger Killer Frost's superpowers as a result of Barry's (Grant Gustin) "Flashpoint" timeline. In the upcoming fifth episode — titled "Monster" — Caitlin comes to her mother for help.

The synopsis from IBT reads, "Desperate to understand what is happening to her, Caitlin visits her mother, Dr. Tannhauser (Susan Walters), a renowned biomedical researcher, in the hopes that her mother can provide some answers about Caitlin's growing meta-human powers. However, when Dr. Tannhauser treats her daughter like a test subject, Caitlin grows cold and brings up past wounds, causing the two to have a major blowout."

Is it possible that the fight between Caitlin and her mother triggered her Killer Frost powers?

Meanwhile, Barry and the team warmly welcome Earth-19 Dr. Wells, but it appears that something is suspicious about him. In the episode 5 trailer, Earth-19 Wells tells himself, "Nobody seems to ask as to why I'm here."

A concerned Cisco (Carlos Valdes) goes through Earth-19 Wells' things and tries to find anything that could help them figure out his motives. However, Earth-19 Wells will catch Cisco snooping around. They will have a confrontation, with Wells asking him, "Is trust not something that you have on this Earth?"

The real reason for Earth-19 Wells' arrival on Earth-2 will soon be revealed in the next episode of "The Flash."

Aside from a mysterious Wells, Barry will soon be facing his biggest villain yet. Entertainment Weekly reports that the Speedster big bad — Savitar — is coming very, very soon to the series.

Executive producer Greg Berlanti adds, "He's the god of motion, so Flash is up against his biggest foe yet."

"The Flash" season 3 airs every Tuesday at 8 p.m. EDT on The CW.