The story takes place in 1963, during the Cold War, when Alisha (Sally Hawkins Sally Hawkins), a dumb girl, worked in a government laboratory as a cleaning woman. When she was young, a serious illness took away Alicia's voice, and ever since, she has lived alone in silence, with only the old painter (Richard Jenkins Richard Jenkins) and colleague Zelda (Octavia Spencer Octavia Spencer). One day, a high-alert alarm sounded in the laboratory, and a mysterious jar full of water was brought in. Alicia was shocked to find that there was a strange creature half-human and half-fish in the jar. Under the leadership of Richard (Michael Shannon Michael Shannon), the team of scientists want to extract the substance that can make biological weapons from this monster, but in Alicia's eyes, it is just a lonely creature like herself. With the passage of time, there was a relationship between Elsa and the monster.