The Case of the Missing Martian MacGuffin

Previously

…As they hurtled through the inky blackness of space, the Earth growing larger in the viewport, Mia felt a familiar pang of satisfaction. Another case closed, another bizarre adventure survived. And as for Zorp, well, Mia suspected they’d be too busy untangling themselves from their own malfunctioning technology to bother with revenge anytime soon. The Cosmic Chronometer was safe, and that was all that mattered. The thought of a well-deserved, and possibly exploding, space-themed ice cream sundae, however, was starting to sound even better.