The connection between Garnet and Capper is that they are both bipedal anthropomorphic cats from animated adaptations of little girls' magical critter-based toylines.

While on a journey to rescue her franchise (Jewelpet) from limbo, Garnet has found Capper preparing to sell the Mane Six into Klugetown's slavery. Mistaking him for an enemy Jewelpet, she immediately knocks him away from the Six to stop him and start the fight.