Set on the fictional New Penzance Island in the summer of 1965, the film follows two misfits: Sam Shakusky (Jared Gilman), a khaki-scout on the run from his foster parents, and Suzy Bishop (Kara Hayward), a brooding bibliophile who keeps a record player and a pair of binoculars by her side.

After developing a pen-pal romance rooted in their shared alienation, the pair orchestrates an elaborate escape. Sam breaks out of his scout camp equipped with wilderness survival gear, while Suzy packs a record player and a suitcase full of fantasy novels. They hike along an old migration trail to a secluded cove, which they dub "Moonrise Kingdom".

: Equally memorable is Hayward, who portrays Suzy with a simmering intensity and a tender vulnerability just beneath the surface. Armed with her mother’s scissors, a collection of fantasy novels, and a pair of binoculars through which she views the world, Suzy is a girl who knows exactly what she wants.

This is the crucial pivot: They are not martyrs. They return to the adult world, but the terms have changed. Captain Sharp lies to Social Services to protect Sam. Scout Master Ward allows his troop to escort the couple to their "marriage." The adults, battered by the literal storm caused by the children’s emotional one, finally concede that love is more important than order.