Does it make sense to say that a movie is predictably unpredictable? And is that a bad thing?
This is one of those movies where for some reason two guys who don't know each other go on a journey, usually against the will of one or both. In this movie, a middle aged torpedo bribes a college kid to follow him around Tokyo. Fukuhara has decided to turn himself into the police, and wants to wander the streets of his town one last time before he goes to prison. He meets hapless college kid Fumiya when he's sent to collect some debt of his. Fukuhara offers to give Fumiya the money he sorely needs in exchange for company. This all happens early, and the majority of the movie is following their walkabout.
They walk through several parts of Tokyo while embarking on random quests born out of their conversations and random curiousness. They meet a bunch of characters on their way, and their journey is filled with weird and silly situations. They go on detours, try new food, get in a fight, and for a stretch they have to pretend to be father and son. There is a lot of humor to be found, but also a good heart, and by the end Fukuhara and Fumiya are much closer to each other than they even realize. The city itself supplies a lot of charm as they move through a few of its many wards, and you really get a sense of the diversity of such a huge metropolis.
The movie progresses like you'd expect an unlikely-buddy/journey movie to. You've probably seen the "first they don't know/like each other much and 'the other guy' has weird habits but hey they've found common ground and now they're friends" thing a dozen times, but as always with movies, it's all in the delivery. The laughs are frequent and come from the weirdest places, and the way the guys bond in this is deeper and more complex than your average (american) movie, which makes it more poignant.
Perhaps my love of silliness and randomness, and my limited knowledge of Japanese culture and filmmaking makes Tenten a funnier, more unpredictable experience to me, but I'd wager anyone who sees this will find something to enjoy.