Aliens in the sky

When Adam and his friends stay up late one night, they see bright lights in the sky. Lights that look suspiciously like flying saucers. Then, the next night, one of the saucers lands by the reservoir, and the creatures who come out of the ship don’t look like people at all. Worse, they want Adam and his friends to come with them for a little ride in space. In fact, the aliens insist, and it doesn’t look like they'll be coming back anytime soon.