One Week Friends may have the preposterous premise of a Lifetime movie, but for the most part it isn't that interested in its own narrative hook. It's far more concerned with everyday happenings, with weekly rhythms and mundane events. With how change emerges from the everyday, how people and relationships evolve amidst the daily cycling of casual, familiar events. Which is, in its unassuming way, as moving as any big drama.

It's hard to pinpoint exactly when something changes in One Week Friends. Each episode is pretty much like the one before: friends talking to friends, meeting new people, discovering new facets of each other; studying together, doing chores together, cleaning the roof, putting up posters; going places together, to the beach, to the crepe cart, to the park; marking the seasons together, making plans for summer, visiting shrines on New Year's. You just kind of float along with them, steeping in the sweetness of their strengthening bonds, relaxed and beguiled by this growing assortment of the gently loveable. And then, somewhere along the line, you look back and realize that everything's changed.

While we are floating, those airy episodes are smuggling in incremental changes to unobtrusively rewrite Kaori and Hase's lives, hiding important developments inside little events. A group study session is an introduction to Kaori's knock-your-heart-out awesome mom, who peels back the cover over Kaori's missing past. Kaori's second friend Saki, on hand initially to dose us with oddball charm, proves to be the doorway through which Kaori rejoins the world. A poster-pasting mishap hints at Kaori's changing feelings. A beach episode confirms Hase's. An offhand comment about Saki by Hase's friend Kiryu reveals itself to be the opening of a subplot that singlehandedly sustains you through the final third.

There's a vein of thoughtful character development, of emotional enrichment, that runs through One Week's meandering little episodes. Through the influence of Hase and Saki, Kaori blossoms, transforming from a frosty outcast, forever afraid of sharing and connection, to a sunny young girl—kind and vulnerable and a true, loving friend. Hase remains mostly unchanged—loyal and gentle and kindhearted to a fault—but he slowly reveals a secret steel, a fire that flares up as a fierce protectiveness (though it is a little like a fuzzy bunny getting mad). We come to know Kiryu as an acid, brutally honest, but wholly trustworthy friend—full of good sense, deadpan humor, and curmudgeonly concern. It becomes clear that he feels and cares deeply, but also that his distaste for bothersome things means he doesn't express it particularly well. Saki… well, Saki's special. She's a chronically easygoing slip of a girl with a memory like a sieve, bursting with careless, lackadaisical charisma and hard-earned acceptance of her own shortcomings. (Her goal in life is to marry a responsible person because she knows from long experience that she can't take care of herself.) She's a light unto herself.

We come to care for these friends, and the show is at its very best when playing poignantly off of that attachment. As when Kaori says goodbye to Saki on their first weekend, Saki happily and heartbreakingly confident that Kaori will remember their wonderful week come Monday, Kaori quietly mourning a loss she already knows she won't remember. Or when Saki tearfully confesses her fears to Kiryu, prompting a reconciliation that just breaks you all to pieces.

These are bittersweet, devastatingly underplayed scenes. If the show had confidence in their power, it would have been nigh perfect. Unfortunately it feels the occasional need to push harder, and that's where things fall apart. The first push lasts only an episode, in which Kaori and Hase have their first fight and the show contrives (emphasis on the contrivance) to wholly erase him from Kaori's life, leaving poor Hase panicked and hurt. The second is more extensive and relies on that hoary shojo device, the outside agitator who upsets the main couple's delicate balance. It casts a shadow over the entire final third, its big, dramatic shifts—at the end of episode nine and the beginning of episode ten—fitting ill with the warm incrementalism of the rest of the show. Eventually the series recovers its gentility, allowing its cast to heal quietly and naturally, but the lapse leaves a scar.

Brains Base and director Tarou Iwasaki engineer a look that is basically perfect for the show: lovely, understated, and faded in the corners like an evanescing memory. Background artistry is especially evocative—lovingly detailed and exquisitely attuned to mood. Watch the way the minimalist design of the school roof whittles the world down to just Kaori and Hase during their lunchtime rendezvous. Or how the haze around the show's edges disappears and the details of the town—a lonely river bank lit by the dying sun, rusted gutters gushing during a rainstorm—jump out when characters are troubled.

Not being a terribly active show, animation isn't hugely important to One Week, but what there is is delicately and sensitively rendered. Character animation is the focus, and it is superb—not showy, but full of individuality and, when need be, freighted with feeling. Iwasaki and his crew match design and movement with care: giving messy-haired, soft-featured Hase a slouchy, disarming locomotion; drawing a clear line between Kaori's private luminosity and her cold, sharp-eyed public demeanor; combining Saki's deadly pixie looks with lethally mellow body language (and Rumi Ookubo's indescribable performance) to form one of the most loveable characters in recent memory.

It's Iwasaki and co. who save the series when it decides it wants bigger drama, performing with class and aching restraint even when the script is trotting out the bad coincidences and bald plot devices and just generally being clunky and crude. (The score, long on subtle piano and significant silences and short on overt manipulation, is also crucial.) It's their steady, discreet hand that disguises the work going on beneath the sweet fun; that makes the show what it is: a sleeper delight, plain and simple.