Nancy meets Mason in 2012 while doing an investigation into the murder of Niko Jovic. He does not like to be bothered while he is working and is openly angry that Niko would look at his work without his permission.
Nancy eventually sees texts between him and Ellie York, the other research assistant whom he claims to hate, indicating that they are working together to sell off Niko's work. When Nancy confronts her, Ellie confirms that they are. Nancy also hears him fighting with Gray Cortright and sees him tampering with the Tesla coil.
At the end of the game, Mason decides to try and break away with Niko's work, but Gray, who made a promise to Niko to destroy the dangerous parts of it, tracks him down at the Technology of Tomorrow Expo, where they have a huge fight. Gray eventually promises that all due credit will remain with him and Ellie if they help him finish Niko's work.
- Mason gets very upset if any of his items are even slightly out of place.
- Mason turned down Los Alamos and a tenure track position to be at Technology of Tomorrow Today.
- Mason alphabetizes his sandwich ingredients.
- Ellie says he is "not human", although he probably just has some form of obsessive-compulsive disorder.
- Ellie tells Nancy that Mason is about sixty percent scientist all the time.