Supernatural's Castiel is road trippin', teaming up with Metatron in order to recover the last vestiges of his original grace.

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Cas (Misha Colins) will bring his nemesis down from heaven and the two heavenly soldiers will spend some quality time in the pimpmobile during "Book of the Damned." Metatron (Curtis Armstrong) knows where Team Free Will's ailing angel can find a scrap of his old grace, and a little threatening from Sam Winchester (Jared Padalecki) will apparently compel him to divulge this crucial information.

It's been quite sometime since Cas has had to worry about his limited angel juice. Crowley (Mark Sheppard) gave him a fresh batch of stolen grace early in season 10 and Collins' character has spent all his time since then looking for a way to cure Dean (Jensen Ackles).

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"This gives him a stay of execution, so he's got disposable batteries. He's got a new set; they're Duracells; they should last for a little while [but] not forever. So it will be an issue that resurfaces again, [but] it takes awhile," Collins informed The Hollywood Reporter back in December, adding that Cas is "sick and tired of making deals with the devil and will [try] not [to] make that compromise again."

So what, exactly, would Collins call teaming up with Metatron? Tune in on April 15 to find out.

Supernatural airs Wednesdays at 9 p.m. ET on The CW. Click the video below to see a preview for the series' next episode, "Inside Man."