Tamamori will be starring in his first lead role of a movie which will be released next year. The title of the movie is "Raintree no Kuni", based on the novel of the same title. The novel is written by Arikawa Hiro, whose other works include Toshokan Sensou (Library Wars), Freeter, Ie wo Kau, Hankyuu Densha, and more.
The movie will be a pure romance story between Sakisaka Nobuyuki (Tamamori), a company/office worker, and Hitomi (Nishiuchi Mariya), the owner of a blog called "Raintree no Kuni". The story starts when the two start to exchange emails with each other.
Without more information being released, it's unknown as to what viewpoint they chose to take with the movie and how much they will reveal in the summary, but I have read the novel before, so just a bit of background information from me.
"Raintree no Kuni" is actually a book within in a book, having first appeared in "Toshokan Sensou". A character who works in the library recommends the book to a library user, and we only get a hint of what the book is about, but it piqued people's interest and Arikawa Hiro wanted to write the story as well, so eventually, this book-within-in-a-book became an actual story that got published.
The reason why the two characters started to exchange emails was because Nobuyuki was looking for reviews of a light novel he liked and he wanted to see if anyone shared his opinion of it because he wasn't satisfied with the ending. He stumbled upon Hitomi's blog during his search and emailed her for a more detailed version of her opinion, and they start to write each other more and such.
Nobuyuki is actually a Kansai person in the original book, but it's likely they will change some of the character details and setting, so who knows how much will be true to the novel.
We'll just have to wait for more details to be announced.
Source: Early release of today (10/29)'s newspaper