Based on true events, this film unfolds in the picturesque setting of Ilha Grande, Brazil. The story centers around João (Pedro Urizzi), a veteran fisherman, who is gearing up to celebrate his son Miguel's (Juan José Garnica) birthday. Miguel, eagerly awaiting his special day, receives a present from his friend Calista (Thalma de Freitas), who instructs him to keep it closed until the party the next day. As João returns from a fishing expedition alongside his companions Marcos (Wilson Rabelo) and Luis (Roberto Borenstein), Miguel expresses his desire to join his father on the next fishing trip. João hesitantly agrees, mindful of Miguel's schooling obligations. Meanwhile, Miguel's mother Maria (Amanda Magalhães) diligently prepares some guava sweets for the village market.
The following day arrives with fresh anticipation as Miguel continues to seek João's permission to accompany him. Ultimately, João consents, and they set sail on their fishing boat. In a shocking turn of events, a violent storm brews suddenly, causing chaos at sea. Despite João's heroic efforts to navigate back to safety, the unthinkable happens: Miguel is tossed overboard and tragically drowns.
Fast forward several years, the narrative transitions to Patagonia, Argentina, where a diligent team of marine biologists studies the penguin migration. This serves as a profound link back to Ilha Grande, where Calista has blossomed into adulthood and is now a mother to a young daughter named Lucía (Duda Galvão). João (Jean Reno) and Maria (Adriana Barraza) are haunted by their past, with João enveloped in grief and resentment from the years gone by; he has abandoned his fishing life, isolating himself from his fellow fishermen.
One day, João finds an oil-smeared penguin on his doorstep, and moved by compassion, he begins to nurse the creature back to health. Maria, returning home from the market, is appalled by the oil stains in her kitchen and expresses her displeasure. Nevertheless, João assures her that they will soon release the penguin back into the wild.
As João cares for the penguin, a special bond blossoms, leading him to craft a small sweater from one of Miguel's old hats. Lucía, enchanted by the creature, joins in and sweetly names it DinDim. Together, João and Lucía embark on a heartfelt mission to set DinDim free. However, much to João's surprise, DinDim chooses to follow him home, and despite João's attempts to persuade the penguin to leave, DinDim is resolute in its decision to stay near.
While walking through their village, the people are astonished to see DinDim trailing after João. Eager to share his story, João leaves a lasting impression on everyone he meets. Eventually, DinDim departs into the horizon after a memorable day with João.
Nestled in the vibrant penguin colony, the researchers' attention shifts to DinDim, noting its extraordinary fearlessness toward humans. The team carefully tags DinDim and observes his peculiar nesting habits, filled with various human discards, but, importantly, they leave his space undisturbed.
As time progresses, DinDim astoundingly returns to João, now adorned with a researcher’s tag. The reunion generates a wave of excitement, and during a village visit, DinDim captures the fascination of onlookers and news emerges about his unique bond with João. An online video of this touching connection quickly spreads globally.
The footage thus reaches the marine biologists in Patagonia, where Adriana (Alexia Moyano) contacts Paulo (Ravel Cabral), a reporter in Rio, looking for confirmation on their unique penguin. Though initially resistant, João is eventually convinced to allow the tag's examination but remains adamant about declining a televised interview.
Meanwhile, Adriana, alongside Stephanie (Rochi Hernández), realizes this peculiar penguin is indeed their own DinDim, known for its sociability. As they make arrangements for filming, Paulo brings a crew to capture the bond between João and DinDim, who visits João every year as they have tracked.
Adriana voices her concerns when she learns that DinDim is slated for relocation to study at the university. Despite a grant offer for research, she stands against her superiors' decision but ultimately, due to her limited authority, she has to plan for DinDim's transport. In a quiet rebellion, she leaves the carrier door open, and once Carlos, another colleague, starts to box DinDim up, he seizes this rare opportunity to escape.
Excitement builds in Ilha Grande as everyone anticipates DinDim’s arrival, yet disappointment settles in when he does not come. João is haunted by a dream of tragedy, and upon waking, finds a gift from Calista among DinDim's things, lending even more weight to the situation.
Days pass without a glimpse of DinDim, and anxiety fills the hearts of those in the village. Refusing to surrender hope, João rallies his fellow fishermen for a search. Their efforts initially seem futile, but João's steadfast conviction leads them into less familiar waters where they finally discover DinDim, worn and drifting at sea. Overwhelmed with relief, João carefully hoists his weary friend aboard, murmur apologies intermingling with the cry of seabirds above. DinDim slowly revives, gratefully accepting a piece of fish from João.
That evening, João’s humble home becomes a lively gathering as Maria offers her famed guava sweets, raising toasts to honor DinDim. As the sun sets in breathtaking colors, they heartfully bid farewell to their cherished companion on the shore.
A heartfelt card, portraying snapshots of the real João and his beloved DinDim, reveals: “DinDim swam over five thousand miles between Argentina and Brazil to visit his friend João for eight consecutive years. It is unknown why DinDim ceased his visits. It is speculated that he found a lifelong mate and started a family.”
