Endings are hard. Plenty of writers will tell you they’re the hardest part of any story, and any movie lover can rattle off a dozen films with lousy endings, from memory.

So when a movie ends just right, it should be savored. The romantic comedy-drama Your Sister’s Sister — new to DVD, Blu-ray and digital this week — concludes with two scenes so perfect that I scanned back and watched them again, just to admire it all. I was investedin this thing, and if the story hadn’t ended properly, I would have had actual trouble sleeping.

It’s the nicest thing I can think to say of the many nice things I’m about to say in regard to this funny, lovely film. Your Sister’s Sister didn’t get the theatrical release it deserved — it never did open in the Triangle — but hopefully it will find its audience on home video.

The story: Iris and Jack (Emily Blunt and Mark Duplass) are platonic best friends, each still in mourning a year after the death of Jack’s brother, who was also Iris’ ex-boyfriend.

Jack in particular is a mess, and after he unravels at a memorial service, Iris sends him off to her dad’s vacation cottage to get his head together. When Jack arrives, however, he’s surprised to find the cabin is already occupied by Iris’ sister Hannah (Rosemarie DeWitt). Hannah is also spiraling, having just broken off a seven-year relationship with her girlfriend.

Jack and Hannah bond over a bottle of tequila and wind up in bed together, despite Hannah’s orientation and Jack’s plumbing. (“I haven’t ridden this bike in a while,” Hannah says.) These things happen when you trifle with the demon rum. But when Iris unexpectedly shows up the next morning, it’s weirdsies for everyone involved.

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