Senku's team reaches the South American coast with the target coordinates (3°7' South, 60°1' West) for the origin of the petrification beam. Crossing the Amazon rainforest on foot is considered lethally risky – due to insects, diseases, and impassable terrain. Instead, Senku plans to bypass it by ship along the Amazon, though this is jeopardized by fuel shortages and Stanley's pursuit.

Meanwhile, the geographer Chelsea joins the team. She became aware through Senku's earlier analysis of petrified swallows and survived isolated in the jungle. Her expertise offers an alternative: A land shortcut through Ecuador over the Andes down to the Amazon. For this, sturdy bicycles are needed – but rubber for tires is missing.

While Kaseki begins building the bicycles, the pursuit situation escalates: Stanley's warship Perseus locates Senku's boat via radar and closes in. As a countermeasure, the team builds a large sail from Chrome's emergency kite, accelerated by Taiju's strength and Ryusui's steering skills. Xeno explains the physical efficiency: With small ships, speed increases quadratically with sail area, while resistance only increases cubically.

Despite the speed advantage, time remains tight: Stanley reaches them at night, and rubber still needs to be procured. The team sets course for Latin America to find the critical material for the bicycles – their last advantage in the race against Stanley's technological superiority.