This is an OVA released on October 27th, 2006. It is also classified as the 13th episode (thus a sequel) to Kashimashi ~Girl Meets Girl~.
Hazumu confessed his love to Yasuna, but she turned him down him. To ease his heartbreak, he went to Mt. Kashimayama where he had met her first. However he lost his way in the mountain, and it was night time. He saw a big shooting star, and when he began to wish, he found out that something was wrong. It was not a shooting star, but it was a falling space ship...