Maggs stated in the series' script book that he felt bound by his promise to Douglas Adams to allow the scripts of the Tertiary Phase to closely follow the plot of the third book; "I myself was willing to give the Tertiary Phase 7 out of 10 on the grounds that I was a little too reverential to the text and the pace suffered as a result." But in adapting the final two novels, the only instructions Maggs got from Adams was "They don't need more than four episodes each." Thus Maggs was able to use many of the major plot elements of the final two books (though not necessarily in the same order), and attempt to reconnect plot threads from all five radio series.