Devon Aire in the Hidden Diamond Caper (1988) (released in Europe as Inside Outing; also known as Raffles) Step into the well-polished shoes of master thief Devon Aire, hired by a bereaved widow to recover her late husband’s vast fortune—hidden in the most unlikely corners of his sprawling mansion. Part isometric puzzler, part real-time adventure, this title combines object manipulation with exploration, all wrapped in an elegant visual style reminiscent of Fairlight. The house is a labyrinth of elaborately furnished rooms, where nearly every object can be picked up, pushed, pulled, or examined to reveal hidden gems. But it’s no ordinary estate—thanks to the eccentric late owner’s fondness for experimental science, the mansion is also overrun with bizarre creatures. Players must navigate traps and monsters, conserve their limited energy, and use both logic and instinct to uncover the elusive diamonds scattered throughout the estate. Originally developed by The Edge and rebranded for U.S. audiences by Epyx, Devon Aire brought its European flair and high-resolution isometric engine to American homes. The result is a stylish, challenging, and charming treasure hunt that rewards methodical players and clever problem solvers.

A very fun and polished game for the time, this intellectual property belonged to The Edge (not the guitarist from U2), which was part of Softek, whose intellectual property was acquired by Edge Games, or so it seems.  There is conflicting information on the Internet as to which Edge entity is the actual rightsholder.  If you want to track it down, you might want to start with https://edgegames.com/ or https://edgegames.com/about.htm.