Warmth in a Puddle Episode 1

In a dimly lit room where only the sound of the ventilation fan echoes, the young man encounters a fish. The fish, distorted in shape, looks somewhat like the young man himself. The fish, which had been lying limp, suddenly jumps up and flies out of the window, floating in the air. The young man stares at the fish as it disappears into a puddle on the street, and becomes transported to a strange space. (Source: Kodansha Creators' Lab)