It's the hottest Christmas on record…

Like naughty and nice, Mariah and Ellie are complete opposites. Small-time actress Ellie is thrilled to be back on set of a cozy holiday film, while makeup artist Mariah only views the low-budget project as a stepping stone on her way to more serious movies. The pair definitely don't hit it off when they're introduced, but if they want to survive the summer heat—and Mariah's stifling Canadian hometown—they've got to keep it professional. Luckily, holiday cheer is Ellie's specialty, and she's determined to win stubborn Mariah over.

Mariah finds one bright spot in her forced second Christmas: hot hookups with an edgy local bartender. The romance even has her opening up to Ellie—who admits to crushing on her wholesome cottage-rental host. But when Ellie and Mariah realize the guys are cheating on them, they band together to get revenge. It's fun planning their own Home Alone–inspired pranks…until Ellie and Mariah realize they're actually falling for each other.

While the ladies grow from friends to lovers, they're aware that the film shoot is too short to get serious. And when filming wraps and new projects pull Ellie and Mariah in totally opposite directions, they’ll have to decide: Was their romance simply a holiday fling or a real Christmas-in-July miracle?