Summer is a time of year when the world has scarcely become accustomed to being alive, with sunny days becoming thunderous, flashing storms in minutes. "Summer 1993," the semi-autobiographical debut feature by writer/director Carla Simón, looks at the season from the quiet, clever perspective of 6-year-old Frida (Laia Artigas, a wonderfully promising child actor), who speaks little but sees every new mystery clearly.

Resilient Frida has a lot to figure out, with literal life and death first on the list. The film throws us into the middle of things, as Frida plays with her friends on the streets of her hometown of Barcelona, watching fireworks explode in the night sky. When she returns to the apartment where she lived with her suddenly deceased mother, she sees her extended family packing up their belongings and trying to decide who the child will live with now. Frida remains calm through it all. She has had too little experience of life to understand how far out of the ordinary all this is.

From the outset Simón puts us in Frida's baffled mind-set, recording the hushed adult conversations around her young heroine with a sense of fly-on-the-wall naturalism, and making us work to figure out who these strangers are, just as Frida does. That first night, the girl takes a long drive with her uncle Esteve (David Verdaguer), her mother's brother, and his wife, Marga (Bruna Cusí). They move Frida to the countryside, where they live in a farmhouse with their daughter Anna (Paula Robles), who seems about 3.

Will the city girl adapt to the rural setting, test her surrogate parents' love and boundaries, learn to deal with her unknown substitute sister? Yes, quite wonderfully.

The immersive "Summer 1993" is almost free of plot but rich with a scrapbook's worth of childhood memories. Her new playmate and the sun-dappled summer they share don't protect her from repressed feelings of resentment and grief. Yet the young girl misses her mother with quiet moments of make-believe (such as her pretend phone call to heaven) that are all the more touching because of their understatement.

As Frida tries to piece together events that brought her to her new home without solid information, we operate like detectives ourselves. There is no mention of AIDS, but it appears that her mother's death, and her father's before that, have left the girl in need of extensive blood tests. She certainly gets a lot of worried attention from the mothers of other kids at the playground when she falls and gets a bloody knee.

Simón understands that no one is ever merely one thing, so she takes critical looks at Frida's sometimes unkind flaws. The film is not a fable of innocence but a tribute to the resilience of life's most vulnerable victims.

The talented actors playing Frida and Anna receive top billing in the film's cast credits, accolades that feel entirely earned. Cusí and Verdaguer are believably warm as Frida's adoptive parents, and as her grandmother, Isabel Rocatti, brings a critical vinegar tone to her dismissive disapproval of her late daughter. Still, watching the little co-stars bring their roles to authentic life without a hint of Hollywood sentimentality is like watching a nonstop magic act.