Episode 9.14

Trapped in a labyrinthine Chinese science fiction epic, Alan faces an ecological catastrophe on a scale of which he’d not dreamed. Peevish interstellar neighbours have sent the Earth an unwanted business card which removes the least useful dimension from the Solar System (up?). The only way to survive is either to flee at light-speed - but Alan’s saucer is still at Kwik Fit - or to have re-engineered one's species to exist in the 2D plane. 

Alan is bravely trying the latter on himself but it would have been helpful to have had time for more than one attempt.