Ponta is a tail-wagging puppy, the beloved pet of the Koizumi family. Then Grandpa Koizumi invents the Guru Guru Bone, which gives Ponta the power to transform into a human girl. Ponta is immediately drawn to handsome Mirai Iwaki, and even after he discovers that she's really a dog, the two fall head over heels (paws?) in love.

When Mirai's ex-girlfriend stands between Ponta and Mirai, the budding relationship sours. Ponta realises that she can never really be Mirai's true girlfriend, so she runs away. And when the lovers try to reunite, tragedy strikes. Will out-of-body experiences, old flames, and spring fever keep Ponta and Mirai apart?