Find out what happens next on Atlantis with a Digital Spy exclusive clip.
Hercules (Mark Addy) is seen leading Ariadne (Aiysha Hart), Pythagoras (Robert Emms) and others into the cave system as they search for Jason (Jack Donnelly), before they stumble upon a gruesomely transformed Dion (Vincent Regan).
Tomorrow night's episode, 'Day of the Dead', sees the fractured Atlanteans struggle to hunt down their friend before he falls prey to an army of flesh-eating monsters.
As Jason fights for his life in the underground warren, he joins forces with the mysterious and magical Medea (Amy Manson).
A seemingly helpful ally, the question remains: can she really be trusted and where do her loyalties lie?
Atlantis continues tomorrow (December 13) at 8.15pm on BBC One.
