Little Twins: Bokura no Natsu ga Tondeiku
Genres: Adventure
Type: Movie, Episodes: 1
Aired: Aug 8, 1992
Studio: Toei Animation
Source: Unknown
Rating: G - All Ages
Synopsis:
The length and quality suggests this movie was the fourth video installment, dumped on theaters as a promotional exercise for the tapes.

(Source: The Anime Encyclopedia)