It's hard to describe the type of series this is. It involves the NEET class and the economical-political attitude amongst Japan's youth toward the older upper-class management. One of these youths, Takizawa, mysteriously comes into possession of a phone that enables him to enact changes in his and others' lives. Fate causes him to meet Saki, a recent graduate seeking employment, and the adventure begins.
The tone of the film is lighthearted, even though the plot deals heavily in political intrigue and adventure. The story is well-written to reveal stepwise all the events occurring before, during, and after Takizawa's and Saki's fateful meeting, including some quirky romance, intrigue, and action. The series ends on a fun and exciting solution to some of the problems that Takizawa encounters along the way, but leaves us with new questions and lead-ins to the following 2 feature films for the series.
I've seen the feature films, and unfortunately, they don't maintain the same level of excitement, mystery, and fun that the original series does. It feels as they're made simply to finish the story lines with logical endings. I'd recommend just watching the original series, and even though it's tough, don't bother with the following feature films to answer the questions created by the series.