In "The Reverse-Flash Returns," the next episode of "The Flash," Reverse-Flash appears in Central City and attacks Christina McGee's Mercury Labs. Matthew Letscher reprises his role as pre-season one Reverse-Flash, who maintains his appearance from before he assumed Harrison Wells' identity.

"The Flash" Showrunner Reveals New Details on Reverse-Flash's Return

According to the official episode description, "When Cisco (Carlos Valdes) gets a vibe of Eobard Thawne (guest star Matthew Letscher), Barry (Grant Gustin) and the team don't believe it. But, after an attack at Mercury Labs, Christina McGee (guest star Amanda Pays) confirms that the Reverse Flash is back. Meanwhile, Iris (Candice Patton) and Francine (guest star Vanessa A. Williams) share a nice moment that brings Iris closer to her brother, Wally (Keiynan Lonsdale)."

Starring Grant Gustin, Carlos Valdes and Jesse L. Martin, "The Flash" returns airs Tuesdays at 8 pm EST on The CW.