The story begins with Igarashi, who was disqualified as a pro golfer after a certain "incident" and thus moves to Kagoshima Prefecture's Tokara Islands to step out of the limelight. On these islands known as "Japan's last unexplored wilderness," he encounters a naive girl named Tonbo.
 
As it turns out, these supposedly unexplored islands have a homemade golf course, where Tonbo plays every day. She demonstrates genius-level prowess, playing every kind of shot with just one golf club, a 3-iron. Igarashi is amazed at Tonbo's talent, even as he harbors doubts about her only using a 3-iron. Yet, hidden deep in Tonbo's heart lies a painful, sad past…. 
(Source: Anime News Network)

[Profile (Arts Vision)](https://www.artsvision.co.jp/talent/14428/) 

Tonbo Ooi, the protagonist, lost both of her parents in a car accident when she was young and was raised by her grandfather, Gonji Ooi, a fisherman on the island of Kagoshima in the Tokara Islands. Tonbo learns to play golf while using her father's inherited No. 3 iron on the island's three golf courses, which were built by the islanders themselves.
 
The story begins with Igarashi, a man who can no longer work as a professional golfer, visits the unexplored Tokara Islands in Japan in search of a job. Igarashi had given up on playing golf anymore, but his encounter with Tonbo, greatly changed his fate.