During the summer of 2010, filmmaker Michael Canzoniero was visiting his in-laws on Shelter Island, New York. Michael's father in-law casually asked if he might be interested in seeing the art gallery that his friend Jimmy constructed in his gas station, featuring a local "outsider" artist. The idea of an art gallery in a gas station was enough to spark Michael's interest, but once he was introduced to benefactor Jimmy Olinkiewicz and artist Harald Olson, he knew there was something extraordinary happening. Michael grabbed his camera and began documenting the poignant relationships and captivating art he saw blossoming before his eyes.

The documentary opens with an introduction to Jimmy Olinkiewicz, who is at once a building contractor, gas station owner, and online antique seller. During the height of his success as a contractor, he bought a local gas station as an investment, intending to flip it for a handsome profit. The financial downturn and abandonment by his wife thwarted that plan, and Jimmy was faced with the prospect of selling the gas station at a loss or simply running it himself. He decided on the latter, turning the aging service station into a local convenience store staffed in part by his autistic son, Alex. As a local entrepreneur who has weathered financial success, financial ruin, divorce, and single fatherhood with a special needs child, Jimmy has an uncommon combination of tenacity and tenderness.

Jimmy takes Michael to meet Harald Olson, a local artist who lives on the outskirts of town and displays his paintings by the side of the road. Harald is a gentle, eccentric soul who subsists on the low wage he earns taking care of an elderly neighbor. All of Harald's remaining energy is spent on his art, which he creates from paint and materials he scavenges from local junkyards.

One day on his way to work, Jimmy drove past a row of Harald's paintings simply leaning up against a fence by the side of the road, and was touched by what he saw. He stopped and sought Harald out, and began purchasing the art to decorate his gas station. Little by little, Jimmy began to learn of Harald's complicated background and his current isolation, which Jimmy could not help but compare with the needs of his own son Alex. Inspired in part by this compelling parallel to his own life, and in part by Harald's clearly profound artistic talent, Jimmy created an art space for Harald in the defunct garage portion of his service station.

As Harald's art is displayed in a public space for the first time, his raw, self-taught mastery of abstract art piques the attention of David Rankin, a local accomplished artist who encourages Harald to show his work to a wider audience. Needing no further convincing of Harald's gift and potential, Jimmy enlists the help of his friends and neighbors to produce a show of Harald's work in a Chelsea art gallery in Manhattan. On their journey towards this goal and through the show's success, it becomes clear that Harald's art is the perfect parallel to Jimmy's kindness: it is innate, beautiful, and wholly unexpected.

Simply put, Shelter Island is an uplifting account of how compassion and human connection can unlock great potential in hidden places.