As a music-video director (Everlong, Fell in Love With a Girl), Michel Gondry excelled at making childlike dream worlds real; as a fiction filmmaker (Eternal Sunshine of the Spotless Mind, The Science of Sleep), he’s best when giving hyper-cinematic form to the raw inner lives of modern man-children. It’s a shock, then, that The Thorn in the Heart, Gondry’s documentary about his own family, is so unimaginative and inaccessible. Sweeping through several decades and French countryside towns to focus on Gondry’s aunt, former schoolteacher Suzette, Thorn is full of stylistic entry points for the Gondry faithful. His signature shabby-chic stop-motion animation sets scenes, while grainy oversaturated home movies are woven into new material (some featuring the director as a supporting player) processed to match. The aesthetics are lovely, but lazily conceived; the best scene is a chroma-key exercise scored to a Charlotte Gainsbourg tune, its function in the film virtually inexplicable. Gondry’s tricks don’t do much to open what is essentially a closed loop. The trouble starts in the first scene: Suzette attempts to tell a story having something to do with her late husband and what was apparently a hilarious misunderstanding involving sauerkraut, but she’s laughing so hard that she can barely get the words out. Her family laughs, too—perhaps they’re familiar enough with this story that they’re getting something we’re not, or perhaps they’re just being polite. Either way, it’s a family bond that Gondry doesn’t let us break through. Watching Thorn is like being helplessly locked out of an inside joke.