The Blue Light unfolds as a frame story with a fairy-tale atmosphere and a sense of mysticism. A modern couple arrive in Santa Maria, a secluded mountain village, driving a convertible, and they notice an intriguing cameo-like photo of a woman in the inn. The innkeeper Max Holzboer asks a young boy to bring the book containing Junta's story, and the tale begins as the innkeeper opens a very large book to its title page.
Junta Leni Riefenstahl is a young woman who lives apart from her fellow villagers around the turn of the century, mostly in solitude with Guzzi Franz Maldacea in the rugged mountains that enclose the village. She spends her days roaming the hills and forests with a free, almost feral innocence, playing among the rocks and trees. To the townspeople she appears shy and mystic, and because of her unearthly calm and ease atop the cliffs, she is branded a witch. When Junta visits the village for any reason, the locals drive her away, convinced she is connected to the strange, escalating deaths of several young men.
On full moon nights, a crack in a prominent local mountain lets the Moon’s light pour into a grotto filled with crystal revelations. The place, glowing with the film’s titular blaue Licht, feels sacred to Junta. The crystals radiate a mesmerizing light that casts a spell over the village’s young men, pulling them toward the grotto’s source, where they ascend and perish under supernatural forces.
Vigo Mathias Wieman is a painter from the city who travels to Santa Maria by a horse-drawn coach. When he sees Junta being harassed in the village square, he is immediately drawn to her and soon falls in love. He later saves her from further hostility and follows her to the cabin she shares with Guzzi, choosing to stay. Their communication is limited by language—Vigo speaks German while Junta speaks Italian—yet their relationship develops in warmth, marked by tenderness and restraint, until the next full moon.
That night, Vigo witnesses Junta climbing the mountain and, entranced by the blue light, follows her to the grotto. He reaches the same sacred space and finds Junta in a state of ecstasy among the crystals, her spellbinding connection with the place clear to him.
Believing he can help Junta by giving her material wealth and by turning the crystals into a shared resource for both her and the villagers, Vigo rushes to warn the townsfolk and explains how they can reach the grotto safely. Junta does not understand his motives until later, when she discovers crystals and tools scattered along the path the following day. Rushing up to the grotto, she finds it emptied of crystals—the villagers have looted the sacred space. Meanwhile, the villagers celebrate the discovery while Junta is left utterly bereft by the betrayal and the outsider’s unwitting complicity. She falls to her death, her spirit crushed by grief. Vigo discovers her body among the montane flowers, the blue cornflower or bluets, and is left to mourn what he has caused.
The film circles back to the opening frame, returning to the modern-day scene, where a last page of the book hints at Junta’s exoneration and a memory kept alive.
