The Shadow Heart stars Sylvester McCoy as the Seventh Doctor (he played the role on TV between 1987-89, and returned in 1996 for the TV Movie), and sees the return of James Wilby (Titanic, Lady Chatterley, Maurice) as Tenebris, whose story continues from the previous adventure, The Acheron Pulse.

Also starring in The Shadow Heart is Chase Masterson, making her debut as the impossibly glamorous bounty hunter Vienna Salvatori. Chase is perhaps best known to science fiction fans for her recurring role as Leeta on the hugely popular Star Trek: Deep Space Nine.

Vienna will return in February for a brand new solo adventure, Vienna: The Memory Box, which is available now to pre-order on CD and download for just £5. That production also stars Tom Price (Torchwood) and Gemma Whelan (Game of Thrones).

The two previous stories in this trilogy are also still available: The Burning Prince stars Peter Davison as the Fifth Doctor, while The Acheron Pulse stars Colin Baker – currently proving a huge hit in the jungle in I’m a Celebrity - Get Me Out of Here! – as the Sixth Doctor.