Beth thinks she has her life mapped out - engaged to the love of her life, with a steady career path in marine biology and a future she could trust. But when she signs on to co-teach a summer field course on humpback whales aboard a tall ship, everything shifts. At sea with her students, her world expands: remote islands, endless horizon, intriguing whale research, and a colleague whose passion for their work, and for her, sparks an affair she can't resist. What begins as a professional partnership becomes the turning point that upends her engagement, her carefully drawn plans for a career and family, and her sense of who she is. On her own and caught between regret and desire, Beth throws herself into the rhythms of research, teaching, rekindling friendships, and the whales she studies from Hawaii to Alaska. Running long miles on land and charting new waters at sea, she begins to question not just whom she loves but also how to build a life rooted in purpose and community.