The trip across Hawaii comes to a close, but not before the team makes some major final breakthroughs: interviews with Gov. David Y. Ige and environmental policy specialist Hoku Ka'aekuahiwi Pousima inspire Tehani to pursue her interest in law, and biologist Chrystie Naeole advises Keakealani and Traven on how they can maintain their unique identities while pursuing their ideas of success.
The road-trippers reach O'ahu, their third and final island destination. While there, they take a once-in-a-lifetime trip up Mount Ka'ala—the island's highest mountain—and visit a private U.S. Army nature reserve at the peak. Then Tehani, Traven, and Keakealani head to the North Shore to check out the infamous Pipe Masters surfing contest and interview Surfline's lead forecaster Kevin Wallis.
Tehani, Traven, and Keakealani visit the U.S. Geological Survey's Hawaiian Volcano Observatory to explore an active volcano zone, and meet with geophysicist Jim Kauahikaua and engineer Kevan Kamibayashi. Then the road-trippers island-hop over to Maui, where their tour of the NOAA Hawaiian Islands Humpback Whale National Marine Sanctuary is crashed by some surprise visitors.
The Season 15 premiere introduces road-trippers Tehani, Traven and Keakealani. They are three college students interested in science, technology, engineering, the arts, and math (STEAM). All three are facing uncertainties—from choosing a major to finding a fulfilling career—and seek inspiration to help them navigate their futures. Their journey begins on the island of Hawai'i, where they meet the scientist who saved Hawaii's papayas.