Boy Meets Mom - Part One

While visiting Mrs. Tendo's grave Ranma begins to wonder about his own mother. Nodoka Saotome, Ranma's mother, had just sent a postcard telling the Tendos she was going to visit. Ranma is quite eager to meet his mother, but Genma explains to everyone that he made a promise to Nodoka when Ranma was first born.

Synopsis excerpt via Kitsu.