The arc marks the return of Tom Baker to the role of the Fourth Doctor for the first time since Destiny of the Doctors in 1997. Baker was the only surviving classic series Doctor actor who had not previously participated in reprising the character for BBC Audio or Big Finish Productions. This also marks Baker's first performance in an original audio drama as the Doctor since Doctor Who and the Pescatons (on LP) and Exploration Earth (on radio), both in 1976.