Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
A space capsule parachutes into a large lake on Earth. When the astronaut sinks to the bottom and struggles to remove her space suit so she can swim to the surface, we see large frogs swimming around her. The camera leaves her to follow one up towards the surface, then returns down to her as she removes the suit. Then it follows her up to the surface and to the shore of the lake, as if she is one of the primordial amphibians that first left life in the water, where she has difficulty moving her legs on land, once again affected by Earth's gravity.