This is a movie version of Tokyo Girl (Tokyo Shoujo), produced by an unlikely named TBS (Tokyo Broadcasting System) producer Tamon-Andrew Niwa . Tamon-Andrew despite his name is a first generation Japanese born in Tokyo.
There's four different TV series and a movie (this one) to this popular drama. First TV series aired in 2003, second seres aired in 2006, third series aired in 2007, and the fourth series aired in 2008. Kaho who starred on the second episode of second TV series, and Kazuma Sano who starred in the second episode of the third TV series plays the lead in this movie.
Miho (Kaho) drops her cell phone at the stairwell by accident. The phone goes through a wormhole and ends up 100 years in the past where Tokijiro (Kazuma Sano) finds it. They realize that they can communicate with each other when the moon is visible. First they don't realize that they are in different time, but gradually they start to realize that each one is telling the truth. Tokijiro send a mirror to Miho by leaving it with the store owner, telling him that a girl will come to pick it up 100 years later. The daughter of the shop owner who was five at the time, but when Miho shows up at the store, now a hundred year old woman remembers Tokijiro's request and hands her the mirror. Tokijiro is aspiring to be a novel writer apprenticing under the famous novelist Soseki Natsume. He asks Miho if he became a famous novelist himself. Miho has never heard of his name, but not only that he's not listed as one of the apprentice of Natsume. He wrote a novel based on their relation, but it's too avant-garde for the taste of his publisher, and gets rejected. The two realities of him being apprentice of Soseki, and not showing up as such in history doesn't match, but one day it becomes obvious to both Miho, and Tokijiro why the time line has turned out the way it did. Tokijiro's novel after 100 years is very much in line with the trend, and becomes the best seller.
The story is quite excellent bitter sweet romance. It's somewhat reminiscent to the original (1983 version) of "Girl Who Leaped Through Time" (Toki o Kakeru Shoujo) in that the main character falls in love with a boy from different time. In this movie, what travels time in is not a person, but a cell phone. The movie is quite stressful to those who are not a native Japanese talker because most of the story happens between the phone conversation of the two main characters, but if one follows their conversation closely, it becomes obvious how well the story is put together.
7.5/10 and recommended for viewing.