|The Great River|
|Season 1, Episode 12|
|Air date||Mar 29, 2015|
|The Well of the Dark||The Battle of Champions|
On Egyxos, Kefer and Bes are inspecting the building of a new dam. Kefer is concerned that several of his workers have gone missing. Bes tries to reassure him that everything will get sorted out, only for more problems to occur.
Back on Earth, a prank by Colin gets both him and Leo detention. They are forced to clean the room together when Leo's bracelet begins to glow. Leo pretends he injured his hand so he can get away from Colin without trouble.
Transporting to Egyxos, Leo finds out someone has attacked the dam. Exaton arrives, thinking Kefer took two of his commanders prisoner. Leo convinces both of the pharaohs to work together to find their missing people.
After some investigating, they find out it is actually the Desert Titans who have been causing the trouble. After being attacked by one, the three Pharaohs fall down into the underground caverns where the Desert Titans are living. After being attacked by more of the creatures, the trio manage to get away.
Exaton remembers that the creatures need an environment rich with salt water to live, learning from a group of Titans that they plan to create an ocean in the middle of the desert. Running away from more of the creatures, they stumble on the missing people who had been kidnapped by the Titans.
While Leo gets everyone out of the hole, Exaton and Kefer defend against the Desert Titans. As the groups escape one of the Titans falls into the hole where salt water springs up, causing him to grow. Remembering his chemistry class, Leo uses the sulfur to send the Titans back underground. With the Titans gone, the truce between Exaton and Kefer ends.
Back at school, Leo uses a little science of his own to clean up the mess before the principal checks on him and Colin.
Bes: "Don't worry, leave everything to me."
Kefer: "That's what's got me worried..."
- — Bes and Kefer.
Leo: "We have to do experiments under water?"
Kay: "Of course, he's going to drown us with boredom."
- — Leo and Kay, showing how much faith they have in Principal McBlizzard's teaching abilities.
"Oh no. I've got to listen to another boring lecture. Just like in school."
- — Leo hates long exposition.
- The Desert Titans appear very similar in appearance to the literary character Cthulhu.