When NASA discovers something strange on Saturn's biggest moon, experts investigate if aliens feeding on the world's electric atmosphere could be the culprit. The disturbing evidence points to a grisly apocalypse if these monsters ever make it to Earth.

When a former Area 51 insider alleges that the Roswell UFO incident was a nefarious Soviet conspiracy masterminded by Stalin, experts investigate if it was indeed an enemy plot against America -- or if the confession is just another cover-up.

When astronomers discover a rogue black hole speeding through the Milky Way, they investigate how much danger this cosmic monster poses to Earth, and what would happen if it ever entered our solar system.

After NASA's New Horizons spacecraft flies by Pluto, it encounters a mysterious object that shuts down the probe's computers. Experts investigate what it could be.

Neil Armstrong led an expedition into the Amazon seeking a library apparently made by aliens. Did a close encounter on his moonwalk inspire his quest?

When NASA begins an experiment to communicate with dolphins, experts examine if it's a prelude to making alien contact. Will it have dire consequences?