The Sea Girl by Ray Cummings is a science fiction novel written in the early 20th century. Set in a near-future 1990 of sub-sea freighters and airliners, it pits humanity against a baffling undersea menace as oceans mysteriously recede and ships vanish without a trace. The story centers on navigator Geoffry Grant, the driven oceanographer Dr. Plantet, his practical daughter Polly, and the dreamer Arturo, who glimpses a girl inside a strange
metallic globe beneath the waves. Their intertwined paths lead to a daring deep-sea expedition and an uncanny encounter with a “sea girl” on a remote Micronesian atoll. The opening of the novel follows escalating Pacific disasters, a glimpse of a luminous undersea globe with a young woman’s face, and worldwide anomalies—abnormal tides, quakes, and volcanoes venting steam—culminating in Dr. Plantet’s stark conclusion that Earth’s honeycombed crust is draining the oceans and that a hidden human-like civilization may be rising to challenge the surface. As governments mobilize and censorship lifts, he builds the Dolphin, a revolutionary craft rated to two thousand fathoms, and sets out with Grant and Polly to scout the Pacific deeps. On the eve of departure, Arturo vanishes, leaving a note and secretly flying to the reported “mermaid” atoll, where he meets a shy, intelligent sea girl and begins to win her trust. Meanwhile, the Dolphin searches westward across the basin, finds no enemy sign, then receives Arturo’s urgent midnight call to rendezvous at the island. The section closes with Arturo waiting by a cave on the moonlit shore after the girl slips back into the water’s darkness. (This is an automatically generated summary.)