A mummified body is discovered in a disused airliner that has been parked in the desert for 6 years. There are indications of a link to an armed robbery at Heathrow Airport six years earlier, and a murder at around the same time. Our team gains two new members. DS Andrea Stephenson takes over for DS Mel Silver, and the new mad scientist is Dr Felix Gibson.

Spencer goes undercover as a prison inmate to investigate the possible reasons for the murders from the man convicted of committing the crimes. To Spence's dismay, the man (who is too scared to say anything about what happened) commits suicide before he can be coerced into revealing who the real killer is.