The first trailer for the fourth season of the CW's The Flash debuted today at Comic-Con International in San Diego. The trailer focuses on Candice Patton's Iris West, who was left behind when Barry Allen dipped into the Speed Force (presumably for good) in the third season's finale. The new trailer hints that Iris' solitude might be coming to an end, though.

The trailer also offered fans their first glimpse at what might turn out to be a major antagonist for season two, though perhaps not the one that was expected. For months now, rumors have circulated that the Thinker would be the season's antagonist, but the new trailer presents a samurai-inspired character with a powerful sword instead. Whether the two are connected remains to be seen.

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The trailer concludes with Carlos Vales' Cisco announcing that he's got a lock on The Flash, presumably ready to pull the speedster from imprisonment in the Speed Force. Set photos from earlier this month suggest the process might not be that simple, as Keiynan Lonsdale, who plays Wally West on the show, was spotted wearing the Scarlet Speedster's iconic superhero getup.

Debuting on October 10 on the CW, the fourth season of The Flash will star Grant Gustin, Candice Patton, Danielle Panabaker, Carlos Valdes, Jesse L. Martin and Keiynan Lonsdale.