Don’t stream I Want You Back looking for the unexpected.

Amazon Prime’s new rom-com, released Friday just in time for the Valentine’s Day season, is a fairly predictable but enjoyable romp starring Jenny Slate and Charlie Day as spurned lovers who team up to get their significant others to take them back.

Slate (On the Rocks) plays Emma, a receptionist who gets unceremoniously dumped at brunch by Noah (Scott Eastwood, Pacific Rim: Uprising), who can’t see their relationship going anywhere, mostly due to Noah’s opinion that Emma doesn’t act like an adult. ( A fair assessment, as Emma still lives in her college apartment despite never graduating and is floundering career-wise.)

Day (It’s Always Sunny in Philadelphia) is Peter, whose longtime girlfriend Anne (Gina Rodriguez, Jane the Virgin), also pulls the plug on their relationship, claiming she wants to take more risks and have a more adventurous life while Peter seems too content with the status quo of his life.

Through the magic of romantic comedy contrivance, Peter and Emma get to know each other while crying in the stairwell of the building where they both work. They bond over their shared circumstances, as both of their exes moved on to new relationships mere moments after dumping them. The two begin to hang out, and hatch a plan to break up their exes’ new situations.

Emma befriends Anne’s new boyfriend Logan (Manny Jacinto, The Good Place) and Peter enlists Noah as his personal trainer. Emma relentlessly flirts with Logan, to the point where she gets invited to a threesome with Logan and Anne. Peter asks Noah to be his wingman, all the while hoping that he can drive a wedge between him and his new girlfriend Ginny (Clark Backo, Letterkenny.)

Though the plot works exactly as well as could be expected (only one of them successfully gets their ex back, and it doesn’t make the happy ending that was desired), the real charm in the movie comes from the acting, not the script, which was penned by Issac Aptaker and Elizabeth Bergen, who do a much better job here than they do with their charmless and unfunny How I Met Your Father sitcom on Hulu.

Though their characters are somewhat ruthless in their desires to get their exes back, Slate and Day make Emma and Peter people to root for. While infiltrating Logan’s life and helping him direct a middle school play, Emma befriends a student and their interactions are truly sweet and moving.

Keep an eye on the faces of Day and Slate, who seem to have a genuine connection. So much of the wonderful chemistry Peter and Emma have together is conveyed by their eyes, or other facial expressions, and even when their characters are at odds you feel something growing between them.

The cast includes Ben McKenzie, Jami Gertz and Pete Davidson, but they only get one scene apiece. The real magic of the film happens when Slate and Day are center stage.

The ending won’t surprise you, but arriving there is an enjoyable journey.