As explored in various MacGyver Science Notes , the episode’s title refers to , a real-world technique used to identify elements within materials. In the show, Mac uses this concept—specifically using X-rays on film to produce infrared light detectable by cameras—to solve a critical puzzle.
For those looking to rewatch, "X-Ray + Penny" is available for streaming on platforms like Paramount+ . MacGyver Season 2 Episode 4 Science Notes: X-Ray + Penny [S2E4] X-Ray Penny
The episode kicks off with a jarring twist: Murdoc successfully drugs and kidnaps MacGyver. Unlike previous encounters, this isn't just about a quick assassination; it’s personal. Murdoc brings Mac to a hidden lair, intent on a slow, calculated torture that involves more than just physical pain—he wants to break Mac’s spirit by revealing disturbing details about his own past, including the mother of his son, Cassian. As explored in various MacGyver Science Notes ,