“Little Green Men” is episode eight of season four of Star Trek: Deep Space Nine.
Nog is finally leaving to attend Starfleet Academy. His uncle Quark has just received a Ferengi shuttle as a gift from a cousin to whom he lent some money some time previously, and Quark agrees to Rom’s idea to take Nog to Earth in it. Quark isn’t doing this out of the goodness of his heart, of course. Instead, he’s using the opportunity to smuggle some illegal goods, although not to Earth.
Unfortunately for them all, the cousin who gave Quark the shuttle really doesn’t like him, and has sabotaged the craft so that it can’t come out of warp. Rom comes up with an idea to break them out of warp using the cargo, and succeeds. They still end up on Earth, but not when they planned. The shuttle crash lands in Roswell, New Mexico in 1947. A familiar date and location.
Quark, when he discovers they have gone back in time, decides to make a lot of money from the humans, and to create the Ferengi Alliance before its time, so that they will be the most powerful race in the quadrant. Things do not go to plan.