The Prime Sentinel, leader of all Sentinels, is overtaken by an evil force, so the Young Sentinels head to outer space to battle the mysterious blob which feeds on energy.
A probe returns from Jupiter with a soil sample, but the moment it's exposed to air, a plant sprouts at an alarming growth rate of 1,000 feet per minute. The Sentinels head to Jupiter to find a solution before the plant consumes the Earth.
A trio of enormous robots are sent to rob a government gold vault in the desert, but soon the machines deduce that they're superior to humans and begin creating an army to wipe out mankind, so it's up to the Young Sentinels to stop them.
Kronos, an agent from the future, arrives to swipe plans which will prevent a space station from being built. When Kronos tries to escape, Hercules and Astraea track him back through prehistoric times.
When the North Pole vanishes, the Young Sentinels investigate and find The Sorceress is responsible. The Sorceress soon makes the Sentinels prisoners of their own imaginations and creates duplicates of them to do her bidding.
A black box emerges from the sea containing Loki, a nefarious telekinetic giant who transports the Young Sentinels to another dimension and commandeers their ship to take revenge on the man who imprisoned him.
A teenage girl, raised by wolves and blessed with the ability to telepathically control wild creatures, launches an attack on an animal testing lab. Complications arise when a wolf mutates into a man-beast and vows revenge against mankind.
The dying Queen Darkari sends a machine from the Inner World to capture Astraea to siphon her brain waves, so Herc, Merc and M.O. journey to the earth's core and mount a rescue.
Morpheus, a villain who received the same training and combined powers given to the three Young Sentinels, comes out of hiding and steals M.O. to copy his memory bank and create duplicates of Sentinel One to fulfill his sinister plans.