‘Insomniacs After School’: A cute film that barely passes the grade

Based on a manga by Makoto Ojiro, Chihiro Ikeda’s heartstring-tugging teen romance “Insomniacs After School” addresses a woefully underserved market: the unfortunates for whom a good night’s sleep is the impossible dream.

As a recovering insomniac, I sympathized with the film’s protagonists — the nerdy Ganta Nakami (Daiken Okudaira) and the bubbly Isaki Magari (Nana Mori) — high schoolers who bond over their chronic sleeplessness.

As a former high school teacher, however, I was surprised to see both Ganta and Isaki stay upright through droning lessons: The usual posture for sleep-deprived students in this country is head on desk.

Isaki discovers a better cure for her insomnia than dozing in class by converting a storeroom by the school’s astronomy observatory into a cozy crash pad. When Ganta discovers her there by accident, she swears him to secrecy. And after confessing their mutual sleep disorders, they come up with an ingenious excuse for napping in the storeroom: revive the school’s long-dormant Astronomy Club, but with only two members.

The opening scenes play the film’s fresh, quirky premise for light comedy, though it soon becomes obvious that this pair shares more than a laughable lack of shuteye. Despite their different personalities — Isaki is an extrovert popular with her clique while Ganta is an introvert with one pal in the world — they become friends and maybe even more.

Here is where the film’s plot engine starts to stall. Insomnia per se is only good for so many gags and sexual exploration of the sort found in Ryuichi Hiroki’s teen film classic “800 Two Lap Runners” (1994) is out of fashion. Hiroki’s uninhibited protagonist and his inamorata of the moment make out in the gym storeroom; Purehearted types, Isaki and Ganta are embarrassed by the accidental bumping of their sleepy heads.

Instead, the laughs give way to lugubrious psychodrama. Isaki, we learn, has a congenitally defective heart and spent much of her childhood in hospitals. Afraid that she might die in her sleep, she fights off drowsiness. Meanwhile, Ganta, whose mother left home while he was asleep in bed, never got over the boyhood trauma. From blaming himself for her exit, he now blames himself for every mishap, including the rain cancellation of an astronomy club event. Once worried that his emotionally distant dad might follow mom out the door, he has also become allergic to sleep.

Having shown us that the protagonists are blameless victims rather than scampish lazybones, the film ladles on the melodrama, beginning with Isaki’s inevitable medical emergency and followed by Ganta’s self-excoriating agonies. Perfervid declarations of eternal love are part of the formula.

Played with a winning naturalness by Mori and Okudaira, both relative newcomers, Itaki and Ganta are likable types, while the adults around them, from Yuki Sakurai’s understanding school nurse to Minori Hagiwara’s cooly perceptive Astronomy Club “OG” (“old girl” or former member), all end up supportive, even if they don’t start that way. In other words, the film is absent of villains, save for the demons lurking in the two principals’ psyches.

For all its loud emotionalizing, “Insomniacs After School” unfolds at a leisurely pace with time out for wide-awake teenaged fun and even personal growth past midnight.