Pisa's ancient harbor, silted over and forgotten by the end of the Roman Empire, turns out to have buried an entire fleet in its mud. Archaeologists excavate the site layer by layer, lifting hulls that were assembled with mortise and tenon joints rather than nails, a construction method that lets them fit together with a precision most viewers won't expect from the period. Interviews with the excavation team walk through what the cargo holds reveal: traces of wine, oil, and spices that place Pisa inside the wider Mediterranean trade network rather than at its edge. The footage lingers on the slow, careful work of freeing timber from centuries of mud without letting it crumble once exposed to air, and on the hull shapes themselves, which the team argues show a more developed sense of hydrodynamics than the standard picture of Roman shipbuilding allows. The film treats the site as an open case rather than a finished story, following the argument from waterlogged timber to a revised account of how Pisa functioned as a working port before it was abandoned and buried.