The fourth and final episode of Doctor Who: The Adventure Games, Shadows of the Vashta Nerada, is now online.

Following on from the ending of third episode TARDIS, it features a plot surrounding a real-world conspiracy and is set in a seabed colony called Poseidon.

The game was initially due to be released on Christmas Day, but as an early treat, fans can now download the episode for both PC and Mac for free from the BBC Doctor Who website.

[Source: BBC Doctor Who website]