The British Guiana 1850 Six-Cent Magenta stamp is fictitious, but is clearly based on the real-life 1856 British Guiana One-Cent Magenta, which is regarded by philatelists as the "world's rarest stamp." Only one is known to exist. In June 2014 the 1856 British Guiana One-Cent Magenta was sold at auction in New York to an anonymous bidder for a whopping $9.5 million (£5.6m), a world's record, and an amount that dwarfed the $300,000 value of the stamp at the center of this murder mystery.
A glimpse into Steve's philatelic past: "I used to collect stamps when I was a kid. Nothing like those, though."
French title: Le timbre de la mort.
The stamp expert, Ed Hawkins, considers the age group 55-60 to be "elderly".