Kanai Dutt, a sophisticated translator from Delhi, is travelling to Lusibari after receiving a letter from his aunt Nilima, inviting him to read a notebook left behind by her late husband, Nirmal. During his journey on the train, Kanai reflects on his past visit to Lusibari as a young boy and the complex emotions it evokes.

We meet Piyali Roy (Piya) as she lands in Kolkata, navigating the chaos of Indian bureaucracy as a foreign passport holder. Piya is passionate about river dolphins and is on a research mission. Her difficulty in communicating in Bengali becomes a barrier, symbolizing her identity crisis and cultural disconnection from her roots.

Piya travels to the Sundarbans with government-assigned forest guards. An uncomfortable interaction with an officer underscores the issues of gender dynamics and misuse of authority. Piya’s solitude is highlighted, as is her sense of alienation in this new landscape.

As Piya enters the dense mangroves by boat, the physical danger of the region becomes palpable. The forest guards treat her dismissively, and one of them behaves inappropriately. The river and the forest seem alive and threatening—a reminder of nature’s power in the tide country.

During an incident when their boat capsizes, Piya is saved by Fokir, a local fisherman. Despite the language barrier, a deep sense of trust develops between them. Fokir’s instinctive understanding of the water and its creatures contrasts with Piya’s scientific knowledge.

Piya chooses to abandon the official government expedition and continues her dolphin study with Fokir, assisted by his young son. The growing partnership between Piya and Fokir highlights the bridging of gaps between science and traditional wisdom, as well as between cultures and classes.

Kanai arrives at Lusibari and reunites with Nilima. She is a stern, practical woman who has devoted her life to social work in the region. Their interactions reveal differences in worldview—Kanai, a worldly man of words, and Nilima, grounded in service.

Nilima gives Kanai the notebook left by her husband Nirmal. Kanai is instructed to read it privately. This mysterious notebook begins to hint at deeper secrets about Lusibari’s past and Nirmal’s life.

Through flashbacks, we learn that Nirmal had grown increasingly disillusioned with his life and longed for purpose. The notebook contains reflections on the political events of the 1970s, including the killing of left-wing settlers in Morichjhãpi—a key historical event.

Kanai begins to read the notebook. He is struck by the poetic, revolutionary voice of his uncle, so different from the mild-mannered man he remembered. The entries blend memoir, political commentary, and philosophical musings.

Piya continues her journey with Fokir. She feels both physically and spiritually connected to him, despite their silence. Her experience on the water with him is almost meditative, marking a turning point in her emotional engagement with the land and people.

Kanai begins to recall events from his youth that are echoed in the notebook. There are references to Kusum, a young woman whose tragic life story is intertwined with the history of Morichjhãpi. Nirmal’s infatuation with her suggests personal guilt and unfulfilled dreams.

The tone of the narrative turns more reflective. Piya and Fokir encounter a pod of dolphins. For Piya, this is a moment of professional triumph and emotional awakening. The tidal rivers become symbolic of emotional and existential depths.

Kanai’s reading of the notebook becomes increasingly intense. He begins to empathize with Nirmal’s idealism and internal turmoil. Questions about duty, guilt, and the meaning of home emerge as dominant themes.

The final chapters of The Ebb section bring together the different narrative threads—Kanai’s reading, Piya’s exploration, and Fokir’s quiet strength. The tide becomes a metaphor for the past sweeping into the present, shaping lives just as the water shapes the islands.