Stana Katic, Nathan Fillion Stana Katic, Nathan Fillion

When ABC's Castle returns on Monday, Jan. 6, Castle (Nathan Fillion) and Beckett (Stana Katic) find themselves under fire — literally.

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In the exclusive clip below, the pair's investigation into the work of what turns out to be a serial arsonist leads them to the home of a pyromaniac who runs a website for people who have fire fetishes. And the case quickly turns personal, when Castle and Beckett discover that Esposito (Jon Huertas) and Ryan (Seamus Dever) may be in danger — or worse, dead.

Check out a sneak peek from the episode below:

Castle "Under Fire" clip

Castle airs Mondays at 10/9c on ABC.