It was the final regular appearance of Tegan Jovanka, who left the Fifth Doctor for the second time. It also marked the return of Davros and the Daleks after their last appearance in Destiny of the Daleks. Lytton makes his debut and, strangely for villains of the time, survives with no ill effects. Notably, this story was separated into two 45-minute episodes in place of the usual four 25-minute ones, a format that would temporarily become the norm during Season 22; the 45-minute length eventually became the established episode length for the series following its revival in 2005.