K-tai Investigator 7 (also transliterated as Kētai Sōsakan 7 — "Cellphone Investigator 7") is a 2008 toku/drama directed by Takashi Miike, about a 15-year-old highschool student named Keita. Having recently moved from out of town with his family, Keita misses his best friend and, as a result, doesn't pay a lot of attention to what's going on around him, and purposely keeps from making new friends. His classmates even begin to call him "airhead-kun".
On a trip to Mt. Fuji he doesn't tell his family about, to catch up with his old friend, Keita stumbles onto the scene of a rampaging construction vehicle, which has been hacked via the internet into causing as much damage as possible. Before Keita and other civilians can be killed, a man named Sosuke Takimoto appears, and attempts to stop the vehicle with the help of his "buddy", a cellphone with near-sentient AI. Takimoto is less successful than he hopes, receiving fatal injuries during the fight, but Keita helps his cellphone buddy, named Phone Braver Seven, stop the rampaging vehicle.
Keita is thus inducted into the secret: Japan's biggest cellphone service provider, ANCHOR, has a secretive sub-organization named Under ANCHOR dedicated to finding people who attempt to commit crimes via the internet and stopping them. Under ANCHOR agents are each partnered with one of the A.I. cellphones for this task. Takimoto was impressed with Keita's quick actions in the fight, and so asks his superiors as his final request to hire the boy on as his replacement. Thus, teenage Keita is partnered with a walking, talking cellphone and becomes a secret agent.
Being a new agent is not easy with his devil-may-care attitude, but things get difficult very quickly as Keita and his new workmates try to stop the machinations of Phone Braver Zero One, the prototype phone who's gone rogue.
K-tai Investigator 7 provide examples of the following tropes:
- Afterlife Express: Third appears on one of these just before his final death near the end of the series.
- All Your Base Are Belong to Us:
- This happens electronically in the backstory, where Zero One hacks into Under ANCHOR's systems.
- Near the finale, in order to keep Under ANCHOR too busy to stop Magira's plans, the police are called in to investigate them.
- Man Behind the Man: Magira is the true Big Bad, not Zero One. In fact, Zero One goes through a HeelFace Turn in the second half of the series, something Magira actually planned from day one.
- Mecha Expansion Pack: The Boost Phones, which can be equipped to Seven and other Phone Bravers to give them additional capabilities:
- Seeker: Used by Seven. Gives him an Infrared Xray Camera
- Speaker: Used by Third. Forms a wall of speakers for listening or combat purposes.
- Demolition: Used by 01. Combat armor, giving him wrist mounted cannons and a combination shield/chainsaw.
- Grinder: Used by Seven. A miniature vibroweapon that's strong enough to melt concrete. Was a Deadly Upgrade before the bugs were worked out.
- Medic: Used by Third. Allows him to perform maintenance on other electronic devices.
- Analyzer: Used by 01. Boosts his hacking ability, to the point where he can even hack into other Bravers.
- Not So Stoic: Seven cannot resist striking up a hero pose whenever he equips a Boost Phone.
- Psycho Prototype: Having lost three Buddies in action has caused Zero One to go rogue, committing all sorts of crimes in an attempt to find out why he exists and what the true nature of the human-cellphone Buddy relationship is.