Stel and Jess investigate a mysterious Greek island where an advanced ancient civilization built a massive marble pyramid. Artifacts there lead them to Turkey where ground penetrating radar reveals an incredible find in the shadow of ancient Troy.

Stel and Jess search ancient underwater ruins off the coast of Greece and follow the trade routes of the Minoan civilization to a circular island and the heart of a volcano where a modern city now sits atop what could be the ruins of Atlantis.

On Europe's largest active volcano, Stel and Jess discover a trail of destruction back to the time of Atlantis, leading them into a hidden labyrinth under a coastal town and to a sunken monolith that may hide the remains of the legendary lost city.

Stel and Jess investigate cave paintings in Turkey that match an advanced civilization that built the world's oldest city. Tracing their ancient migration to the coast they discover a shifted shoreline and ruins of a lost city right under their feet.

In Croatia, Stel and Jess dive for relics and find evidence of a lost city.

Stel and Jess investigate a golden grave that could be a king of Atlantis.