Shepard is a founding member of the Scientific Boys Club alongside Cooper and Gordon. The club originated in their childhood, sparked by Percival Lowell's theories about Martian life and canals, forging their shared lifelong ambition to travel to Mars.

Fifty years after the club's formation, Shepard remains dedicated to this dream. He actively participates in constructing an interplanetary vessel designed to sail the "Ethereal Current," utilizing repurposed submarine and airship components. This project relies on outdated scientific theories involving light-bearing ether for propulsion.

Shepard embodies persistent idealism and devotion to childhood aspirations. His personality contrasts with the pragmatic outlook of Windy, Gordon's daughter, who assists with calculations while maintaining a grounded perspective. Shepard's unwavering commitment drives him to join the risky Mars voyage in his old age.

He appears in both episodes of the Scientific Boys Club OVA arc, depicting the club's efforts to build their spacecraft and undertake the journey. Shepard is also present in the exclusive short "Sake Cup of Miss China," included within the group narrative. His portrayal remains consistent as part of the trio united by scientific curiosity and nostalgia.