The countdown begins in the upcoming episode of "The Flash" season 3.

Titled "Infantino Street," next week's episode will see the return of Captain Cold (guest star Wentworth Miller). According to the official synopsis, only 24 hours is left until Iris (Candice Patton) is murdered by Savitar (Andre Tricoteux). Although his latest mission proves to be very difficult, Barry (Grant Gustin) decides to use any means necessary to save the love of his life. Barry later discovers he only has one option left to save Iris, so he seeks help from Captain Cold.

The CW has released a new promo for the episode, which highlights Barry's moments with his former adversary. Barry tells Captain Cold that they need to steal a power source and use it against Savitar. The latter calls the former a "thief" because of his plan, but he still agrees to help him out. At the end of the clip, the duo are seen hiding beside a door guarded by a shark. "I can't believe they turned King Shark into a guard dog," Barry said. "King Shark, that's adorable," Captain Cold responded with a laugh.

Previous episodes of "The Flash" have already revealed that Savitar is actually a future version of Barry. Aside from giving more answers about how things turned out that way, the episodes leading up to the finale will also raise a conundrum for Barry. Executive producer Andrew Kreisberg told Entertainment Weekly that one episode will see Barry think about the villains he has fought with.

". . . He [Barry] says that so many of these bad guys that we've fought, I didn't understand why they were doing what they were doing," Kreisberg said. "They just seemed to be filled with so much hate and anger and did terrible things, I would look at them and be like, 'Why are you doing this?' But when Barry looks at Savitar, he sees it and he kind of understands it."

The third season of "The Flash" airs every Tuesday night at 8 p.m. EDT on The CW.