The Hitchhiker's Guide to the Galaxy Specials Episode 31 Hexagonal Phase Trailer ( Air Date 2018-02-02 ) Genre Comedy, Sci-Fi & Fantasy category. Overview "Made by Perfectly Normal Productions for BBC Radio 4, adapted by Dirk Maggs from the Eoin Colfer book And Another Thing.. plus some material newly discovered among Douglas Adams' papers. Once again, surviving cast members gathered at The Soundhouse in London, and welcomed some wonderful guest stars including Mitch Benn, Ed Byrne, John Lloyd and Sir Lenny Henry, with Jim Broadbent as Marvin.".