"Best in Show, Bets Across the Stars" follows the dual narratives of Major Cholmondeley Featherstonehaugh, who is earnestly preparing his Wire Fox Terrier, Sir Reginald Wobblebottom, for the prestigious Westminster Kennel Club Dog Show, and Vinnie 'The Poodle' Groblax, the alien head of the Interstellar Turf Accountants' Conglomerate (ITAC). For ITAC, the Westminster show is the galaxy's largest betting event, and when the favorite, Fluffybutt the Third, threatens to cause a massive payout, Vinnie initiates "Operation: Best in Show." This plan involves an ITAC operative, Agent Barry, covertly swapping Sir Reginald with Kz’sorp, a bio-engineered Grulacian Slime Hound programmed to mimic the terrier, all to manipulate the odds and protect ITAC's profits.

As Kz’sorp navigates the show under the unsuspecting Major's handling and Barry's anxious remote piloting, it faces numerous challenges: near-detection by judges due to its artificial nature, glitches caused by external stimuli like flashbulbs, and the persistent threat of Barnaby, a Bloodhound with an uncanny ability to smell the alien imposter. Despite these hurdles and several close calls that Vinnie Groblax monitors with fluctuating fury from his asteroid headquarters, Kz'sorp manages to secure second place. This outcome is profitable enough for ITAC, and Barry successfully retrieves Kz’sorp, returning the real, albeit temporarily disoriented, Sir Reginald to a bewildered Major. The Earth remains completely unaware of the interstellar gambling and high-stakes substitution that just unfolded at its premier dog show.