The Mistress

Arli and Karli are identical twin earth nymphs. Joon and Earl, a human couple who couldn't have children of their own, find the twins before leaving Earth to help found the colony on Triton, one of the moons of Neptune. Their boss, a rich entrepreneur named Josef Roseblood has many secrets. When Derrick, a young man with a reputation of discovering secrets goes to Triton, Roseblood finds him threatening the small colony. With one of the twins rebelling against her upbringing, and a disease killing Joon and Earl and no vaccines available on the colony, it's not clear who or what the real threat is.