It's remarkable how math equations and numbers work out to be the most interesting elements of this story. The film looks nice and has endearing and adorable characters but no ooomph! The 'gimmick' of the film, that the professor's memory only lasts 80 minutes (except for events that happened prior to 1973), barely gets any mileage and doesn't seem too stringently enforced. The film won't offend anyone but is not likely to excite too many either. It's just a tone poem to niceness and a restrained passion for numbers. Not that there's anything wrong with that. There was drama waiting to explode but never addressed: the real relationship between the professor and his "sister-in-law".
It's about a Professor that has his memory for only 80 minutes. After that he will start from the beginning again and again. The maid and her son become closer and closer with the professor and the story just roll around about the maid`s son. "Root" tells the story about he and his professor.