"Shada" was a six-part serial written by Douglas Adams that was scheduled to conclude Season 17 and be broadcast from 19 January - 23 February 1980. Production was halted during studio recordings due to a strike, with the remaining studio scenes never being recorded, and the serial never transmitted. A reconstruction of the serial using the Fourth Doctor's narration and existing footage was later released on VHS in 1992. The story was later adapted by Big Finish in 2003 as a webcast production featuring Paul McGann's Eighth Doctor (and later released as an audio story that same year), while Adams himself reused elements from the serial for his first Dirk Gently novel "Dirk Gently's Holistic Detective Agency". The story was novelised by Gareth Roberts in 2012, and completed with animation in 2017, with most of the original cast returning to play their original roles.