In Greece, the O'Connell family are translating a slab with ancient Greek characters on it: the Scrolls of Thebes were once part of the ancient Grecian ship, the Athena, and all that is needed is to find the ship’s log to see where the scrolls were dropped off. The slab states that the Athena made berth in the ancient city of Minosos, and the plan is made so that all that’s needed is to head to Minosos and take the ship’s log, but Minosos was said to have been swallowed up by the sea at around 400 B.C. As Evelyn is translating the line explaining that the “fist of Zeus came crashing down”, a rotted fist punches a hole through the slab, throwing Rick backwards as Imhotep steps out from behind the slab, demanding “what is rightfully” his and upon being denied, attempts to strike Evelyn, but Rick uses his bullwhip to lasso the mummy’s arm, halting him for a moment before Imhotep tosses Rick against a pillar before proceeding to strike Evelyn aside and reaches Alex, who unknowingly uses the Manacle of Osiris to blast Imhotep backwards. While the mummy is unconscious, the family escapes, with Evelyn taking two fragments of the shattered slab, and on the drive back, Evelyn can extract no information from one piece, but Alex holds the other, and with the Manacle’s powers, experiences a vision of himself in a library located in what was once Minosos: in the vision, Alex finds the Athena's log as the buildings begin to crumble and fall as the entire island sinks, taking with it the ship’s log Greek and Alex himself. Alex leaves his vision and states that Minosos was located off the coast of Crete, and that the ship’s log was on the island, through his vision. Evelyn declares that she knows of a way to get to the sunken ruins.
Meanwhile, Imhotep comes to and uses his powers to piece together the slab, save for two pieces, and remarks that ancient Greek, the language in which the slab is inscribed, is “a most poetic language”.
The family reaches Crete and Evelyn relishes being out in the salty sea air, while Rick’s allergies worsen with Tut around, when a submarine emerges from the water and driving it is a Greek archaeologist named Dimitri Helios, who has heard of Evelyn and lays his charm on her, kissing her hand. Getting back to the matter at hand, Evelyn offers Dimitri the chance to find Minosos, which Dimitri at first derides, as none have ever found it but accepts the challenge, as the reward of working with the famed Evelyn O'Connell is payment enough. Rick is somewhat jealous at Dimitri’s advances at his wife and is left alone to load the equipment into the watercraft. Later at sea, Dimitri lets Alex drive his submarine, giving him lessons on how to drive it all the while as Rick wonders aloud to Evelyn what Dimitri has that Rick hasn’t but at that moment, Alex spots a waterspout approaching which Dimitri dismisses as nothing unusual. Rick, however, knows better that it is Imhotep and tells Dimitri to dive the submarine, escaping the waterspout.
As the watercraft dives, however, Imhotep himself appears, having transformed himself into the waterspout, and holds onto the diving craft as Dimitri drives it down. Imhotep begins pounding the ship’s hull with his fists, severely denting it and causing Dimitri to call out that he’s tearing the hull and that no human alive could do it, to which Alex states that the source of the hull’s tearing-apart is no human but rather a three-thousand year old mummy. As the submarine goes deeper, Imhotep continues to pound down the hull and Dimitri decides to drive the submarine deeper still, causing Imhotep outside to screech out in pain, releasing his hold on the submarine hull, but the vessel crashes into two underwater mountains and begins to lose control. Dimitri cannot regain control of the craft as it sinks farther down into the waters, and Evelyn suggests putting it into reverse but the speed and depth of the submarine would cause it to tear apart. Rick then sarcastically suggests stretching his leg out and stopping it with his foot, giving Dimitri the idea to use the ship periscope to scrape against the mountainside, stopping it from sinking into an abyss. Alex marvels at Dimitri’s action, with Rick sullenly stating that he gave him the idea to begin with.
Meanwhile, on the surface, a Greek fisherman aboard his fishing trawler pulls in his nets and finds Imhotep, who roars furiously once he cuts his way from the net, causing the fisherman to jump out of the ship screaming. Imhotep then peers down into the waters, where the submarine’s hull has given way and water bursts in through the screws holding the walls. Rick walks forward to seal the cracks but Dimitri stops him from going further: the submarine, being at the angle it is, could be tipped into the abyss by even the slightest shift in weight, and in the abyss, the submarine would be crushed like a tin cup. Alex volunteers himself to repair the ship’s holes as he weighs less than the adults and his parents reluctantly allow him to try as he walks slowly and softly to the cabinet where the toolkit is kept. Up at the surface, Imhotep summons an ancient sea monster from beneath the ocean floor.
Upon finishing welding the edges, Alex lets the blowtorch down and it topples over, rolling to the driver’s seat and causing the submarine to sink into the abyss, where it is stopped from sinking down further when it lands in between two rock sides. Looking out through the window, Evelyn sees the ancient sunken city of Minosos when a loud crack sounds behind her, and the ship’s hull continues to leak out water. Rick asks Dimitri how they might get there and Dimitri shows Rick a project that a friend of his had been working on: the Self-Contained Underwater Breathing Apparatus, or SCUBA. Dimitri, however, has only three suits and suggests that he go to find the information they seek from the sunken city while Rick and Alex work on the bow plates outside the submarine while Evelyn seals the holes inside but Rick disagrees, stating that it is Dimitri’s craft and that Rick won’t allow Alex or Evelyn to get too far from the ship; Rick points himself out as the most logical choice to go.
Meanwhile, the sea monster that Imhotep summoned grows closer to the vessel as it swims at a great speed. In the submarine, Alex draws up a diagram of the location of the ship’s logs, which he saw in his vision, to which Dimitri replies that the vision might be wrong but Rick replies that it has not been thus far, trusting in Alex and sealing the diagram of the city in a jar. Rick, Dimitri and Alex suit up and leave the ship, equipped with radio transmitters to speak directions to Evelyn, so as to repair the outsides while Evelyn welds the interiors together. While the three are fixing a dent on the outside, the sea monster that Imhotep summoned draws closer to them and they do not see it but Evelyn does and tries to warn them but the radio transmitters have gone out. Evelyn uses the blow torch to bang against the windows in Morse code, stating “Danger behind you” as the sea monster draws closer and chases Dimitri and Alex away. The monster collides with the sub and contorts its face to resemble Imhotep’s as it approaches Dimitri and Alex and reaches the propellers, where it is blasted away by a jet of water that Evelyn generates by pressing a button. The monster swims back and loosens a giant rock at the top of the abyss which lands atop Dimitri and Alex. Alex emerges from beneath the rock unharmed but Dimitri’s air supply has been cut, causing Alex to swim back to the submarine with Dimitri. Once Dimitri reaches the submarine he is asked by Evelyn where Alex is but Dimitri explains that Alex was with him a moment ago.
Alex swims off alone to Minosos’ sunken ruins to warn his father but knows that he won’t get to the ruins fast and catches a ride from a group of manta rays to the ruins as Rick swims closer, praising Alex’s work with the map. Evelyn and Dimitri are repairing the submarine sides but the holes appear faster than they can be fixed, to which Dimitri states that they will need to pump out the water first or be too heavy to take off when Rick and Alex return. Rick, meanwhile, has reached the library and found the Athena’s log on a shelf but notices that it is booby-trapped and at the moment, the sea monster returns and attacks. Rick picks up a sunken pillar and bats the monster away with it as Alex swoops in on the manta ray he rode on with a vase that he took, smashing the monster’s head with it and causing it to crash into a wall. Alex tells his father that he came to warn him about the monster as it gets up from its crash and swoops in, chasing the manta away. Having no second escape plan, Alex swims away to a nearby statue and is cornered by the monster; in desperation, Alex attempts to activate the Manacle of Osiris but it doesn’t and Rick pushes another statue onto the monster, slowing it down for a moment. At that moment, Rick and Alex swim back to the shelves and Rick warns Alex to be prepared for whatever may happen as he takes the Athena’s log off its shelf, causing the ceiling to come crashing down and Rick takes his oxygen tank, tearing its seal open so that the air pressure causes them to be launched out through the doorway as debris comes crashing down. The monster is trapped inside and crushed by the falling rocks, to Imhotep’s fury.
Rick and Alex return to the submarine, with Alex providing Rick with air from his tank and the pair returns to the submarine, whereupon Rick gives a contented Evelyn the logs and Dimitri is thanked by Rick for his help as he states that the holds have let out enough water and they can safely return to the surface. In the sub, Rick tells Alex that he has been feeling jealous of Dimitri and that he is not as good as Dimitri is, to which Alex replies that Rick is better, for he is Alex’s father.
- Jim Cummings - Imhotep
- Grey DeLisle - Evelyn O'Connell
- Christopher Marquette - Alex O'Connell
- John Schneider - Rick O'Connell
- John Kassir - Dimitri Helios
- Rick O'Connell
- Evelyn O'Connell
- Alex O'Connell
- Dimitri Helios (First appearance)
- Greek fisherman (First appearance)
- Alexander the Great(Mentioned only)
- Osiris(Mentioned only)
- Zeus(First mentioned)