Love Position - The Legend of Halley (OAV)

An agent who was sent riding on Halley's comet to the earth. He was actually given an order to destroy the earth. Captivated by planet's beauty, however, he is no longer able to destroy the planet. Seventy-six years later, another agent from Halley's comet is sent to the earth to liquidate this traitor, who is now disguised as a girl named Lamina in Vietnam.

An alien agent riding on Halley's Comet arrives on Earth. This alien was sent to destroy the planet, but captivated by its beauty, they are no longer able to do so. Seventy-six years later, as Halley's Comet once again approaches the Earth, another agent is sent to eliminate this traitor, who is now disguised as a girl named Lamina, and is living in Vietnam.

"Sugao no mama de" (素顔のままで) by Yoko Nagayama