Carlton is an android (a 4.5 Bowie Artificial Intelligence Robot) who works for two comedians on the outer vaudeville circuit of the solar system known ironically as "The Road to Mars". His problem is that as a computer he cannot understand irony, even though he is attempting to write a thesis about comedy, its place in evolution, and whether it can ever be cured, while studying the comedians of the late twentieth-century (including obscure and esoteric comedy acts such as Monty Python's Flying Circus) in his search for the comedy gene.

In the meantime, while auditioning for a gig on "The Princess Di" (a solar cruise ship) his two employers inadvertently offend the fabulous diva Brenda Woolley and become involved in a terrorist plot against Mars, the home of Showbiz.

Can Carlton prevent Alex and Lewis from losing their gigs, help them overcome the love thing, and finally understand the meaning of comedy in the Universe? Will a robot ever really be able to do stand-up? As Einstein might have said, nothing in the universe can travel faster than the speed of laughter.