Christopher is a boy who wants to be a sailor at all costs. However, his father Dominic wants his son to become a textile craftsman like him, instead. After the downfall of the Fregosa family with whom Dominic Columbus had sided, he becomes more available to his son such that Christopher can finally go aboard a ship. It is then that young Christopher becomes friends with a very good sailor named John.

On his first sea voyage, young Columbus visits the Isle of Chios; it is then that he first experiences life aboard a boat and "learns the ropes" of sailing. One day, the captain decides to cancel a port of call to ensure a swifter arrival, a decision which greatly upsets the sailors; for this he promises two days of rest at Chios. However, after only a brief stay at the Isle of Chios, the captain decides to leave again immediately, promising the crew double their regular pay; most of the crew go along with this, but John does not agree, fearing a storm.

The ship on which Columbus has boarded leaves the isle of Chios. Notwithstanding, John, fearing that a storm is approaching, has a discussion with the captain in the hopes of persuading him to wait the storm out. Unfortunately, the captain does not take kindly to John's point of view, and for this, has John locked under the deck. That night, the ship collides with a rock before the storm sets in. Unfortunately, in order to save the ship and the lives of the crew, John must sacrifice his own life.

Columbus sets sail as the chief sailor on a cargo vessel en route from Genoa to Lisbon transporting precious loads of contents. Having passed the Straits of Gibraltar, the fleet then encounters pirates off the coast of Saint Vincent's Cape. The Genoese crew tries to escape from the pirates, but to no avail; they are soundly defeated, and their ship is sunk. Shipwrecked, Columbus finds himself at the mercy of the waves.

Having survived the shipwreck, Columbus arrives at the village of Lagos where he takes shelter in a monastery. Having been rejuvenated, he sets sail once more until reaching the port of Sagres. Rather than return home, Columbus decides to go to Lisbon in order to learn everything possible about marine sciences, and to more fully dedicate himself to exploring the seven seas.