Who was it that did something very naughty to the fireman? Was it Peter Sellers as the stranger on the train? Or John Wells and John Fortune as the commuters? And why does Roland MacLeod remain so silent? Or the mad composer Carl Davis masquerade as Liszt? And is Madeleine Smith as innocent as she looks? Percy Edwards as the pterodactyl and master detective invites you to help him sort Out the clues in tonight's nerve-twanging whodunit.