S13 E1: Halley's Comet: Once in a Lifetime

S13 E2: Goddess of the Earth

S13 E3: Horsemen of China

S13 E4: Life's First Feelings

S13 E5: The Case of the Frozen Addict

S13 E6: Toxic Trials

S13 E7: Skydive to the Rain Forest

S13 E8: Return of the Osprey

S13 E9: The Rise of a Wonder Drug

S13 E10: When Wonder Drugs Don't Work

S13 E11: Visions of Star Wars

S13 E12: The Search for the Disappeared

S13 E13: The Planet that Got Knocked on its Side

S13 E14: High-Tech Babies

S13 E15: Can AIDS Be Stopped?

S13 E16: Is Anybody Out There?

S13 E17: Mystery of the Animal Pathfinders

S13 E18: Are You Swimming in a Sewer?

S13 E19: Sail Wars!

S13 E20: Leprosy Can Be Cured!

S13 E21: How Babies Get Made