Diving into the Unknown (original title Takaisin pintaan) is a 2016 Finnish film directed by Juan Reina.

When the official recovery operation is called off by the Norwegian and British authorities after being deemed too risky, the friends set out on a secret mission to retrieve the bodies themselves.

The film opens with footage of a group of Finnish divers attempting to swim through a cave system in Plurdalen, Norway.

[3] Despite this, the survivors of the original diving team planned a covert but well-supported return expedition to retrieve the bodies of their friends.

[4] They were accompanied by the documentary crew that had originally begun filming their attempt to swim through the cave, and the dives were recorded on helmet-worn cameras.