The Urusei Yatsura story comes to a climax in this animated retelling of the final Manga story (although not the final movie). Lupa, yet another one of Lum's fiancés, arrives on the scene, and Lum and Ataru have to repeat their game of tag in order to prevent the Earth from being destroyed.

All Ataru has to do to win is say "I love you" the three words he has steadfastly refused to say to Lum. Will he admit his true feelings and save the Earth? Or will his pride doom it to destruction?

(Source: AniDB)

Lupica, another one of the legion of space princesses that all seem to have found out about Earth in some tour book, appears and abducts Ataru! 

But Lupica isn't after Ataru for his great looks or charming personality (because he doesn't have either). Lupica's goal is the greatest love potion in the galaxy, which she intends to use to induce her sweetheart to tie the knot. To get it, she needs the possessor of the greatest lust in the universe...

(Source: AniDB)

It is Tetsuya Kuroko's birthday. In celebration, Satsuki Momoi has invited the other members of the Generation of Miracles to play basketball together and rekindle the memories from their nostalgic middle school days. Meanwhile, Taiga Kagami and his fellow teammates of Seirin High are doing their best to prepare for Kuroko's birthday party. Sometimes, the best gift one can receive is not a material one but, rather, the feeling of having fun with everyone!

The story is from manga volume 23.