Lum doesn't need much assistance going ballistic when everyone in Tomobiki gets an invitation to Ataru's wedding... and she's not listed as the bride! It seems that some 11 years ago, Ataru played "Shadow Tag" with a young girl named Elle and won. Unfortunately, Elle was yet another Alien Princess; and on her planet, if a boy steps on a girl's shadow, they have to marry.
When Elle's emissary comes to make arrangements, Lum redefines the term "the atmosphere was electric," but to no avail: a force-field now protects Ataru from her high voltage love-zaps. Lum's friend Benten suggests a pre-emptive wedding, and they proceed to abduct Ataru and all of the wedding guests, and the stage is set for the shotgun wedding of all time!