As the fisheries expert Alfred Jones navigates an unexpected email from financial adviser Harriet Chetwode-Talbot, he is presented with a proposal that borders on the absurd: establishing a salmon fishing endeavor in Yemen, backed by a wealthy sheikh and the Foreign and Commonwealth Office. At first, Alfred brushes off the idea as "fundamentally unfeasible" due to Yemen's inadequate environment for salmon, despite Harriet trying to educate him on the exceptional conditions of the country.
Amid this, Patricia Maxwell, the press secretary for the British Prime Minister, recognizes a potential for improving Britain's relationship with the Islamic world through this uplifting narrative. She pitches the concept of salmon fishing in Yemen to the Prime Minister's office. Under pressure from Patricia's influential encouragement, Alfred's superior insists that he take part in the project, placing him in a difficult position as he grapples with the risk to his professional reputation.
With financial stability at stake, largely influenced by his wife’s counsel, Alfred reluctantly consents to embark on this venture. Harriet orchestrates a meeting between Alfred and the sheikh at his picturesque estate in the Scottish Highlands, where Alfred is introduced to the visionary behind the famed "Woolly Jones" fishing fly, a renowned fishing lure. While Alfred acknowledges the project's inherent absurdity, the sheikh's unwavering belief in the power of fishing to foster unity and promote goodwill leaves a profound impression on him.
As Alfred's wife takes up a new role in Geneva, he immerses himself in the salmon initiative, discovering a newfound sense of purpose alongside Harriet. Their camaraderie blossoms into a shared passion, leading to promising advancements in their project, yet they face an emotional setback when Harriet discovers that her boyfriend, British special forces Captain Robert Meyers, has gone missing in action. Heartbroken, Harriet retreats into solitude, prompting Alfred to visit her—not to discuss work, but to provide solace.
Amidst their challenges, the sheikh persists against fierce opposition from radicals who condemn him for introducing Western ideals. Meanwhile, Patricia informs him that public sentiment in Britain necessitates the use of farmed salmon rather than depleting wild stocks. The sheikh, however, remains skeptical about the viability of farmed salmon, ultimately deciding to withdraw his support for the British government’s involvement in the project.
Left without governmental backing, Alfred makes the courageous decision to resign and continue pursuing his vision of launching salmon fishing in Yemen, firm in his belief that it could bridge cultural divides and foster understanding among communities. However, the stress of his troubled marriage weighs heavily on him, leading to a decisive moment where he persuades the Sheikh to embrace the idea of utilizing farmed salmon.
An unexpected crisis arises when a Yemeni extremist attempts to assassinate the sheikh while they fish, but Alfred's quick reflexes save the day, suggesting that there's more at stake than just business. As the bond between Alfred and Harriet strengthens in the face of adversity, they continue to find solace in their shared mission against the stunning backdrop of Yemen.
At a pivotal press conference, Patricia orchestrates a reunion between Harriet and Robert, whose unexpected return from the dead leaves Alfred grappling with heartache. That evening, as Harriet begins to question her feelings for Robert, Alfred receives a message from his wife that leads him to decline her request to come home.
The following day brings the long-awaited moment when the fish are introduced to their new environment, creating an atmosphere of celebration as they begin to swim upstream. Meanwhile, Robert and Patricia utilize the occasion for a photo opportunity, but calamity strikes when terrorists breach the dam upstream, triggering a cataclysmic flash flood that wreaks havoc on the valley. Although the majority escape with their lives, the destruction left in the wake of this tragedy is overwhelming.
In the aftermath, the sheikh, tormented by guilt, pledges to rebuild the community with the active support of the locals. As Harriet prepares to leave with Robert, he expresses heartfelt gratitude for her unwavering support during his trials, clarifying that she is indebted to no one. With a heavy heart, Alfred bids her farewell, wishing her all the best as he contemplates his uncertain future.
Just as Harriet is on the verge of departure, both spot a salmon leaping from the river—a powerful symbol of resilience. In that moment, a revelation dawns on Alfred, as Harriet subtly asks if he might need a partner—a question that resonates deeply within him. As they share a tender embrace and clasp hands, gazing out at the flowing river, it becomes evident that their extraordinary journey is just beginning.
