Overview

In a Mars base, the inhabitants are being infected by a mysterious water creature which takes over its victims. The Doctor is thrust into the middle of this catastrophe, knowing a larger one is waiting around the corner.

Details

Cast

David Tennant

Lindsay Duncan

Peter O'Brien

Sharon Duncan-Brewster

Gemma Chan

Aleksandar Mikic

Michael Goldsmith

Cosima Shaw

Joplin Sibtain

Alan Ruscoe