SPEC: Birth revolves around a pair of police detectives as part of a special division solving difficult cases. Touma Saya is a woman with an IQ of 201 and an inability to "read the atmosphere" in social situations. Due to a previous case, her left arm is in a sling. Her partner Sebumi Takeru used to be the star performer of the Metropolitan Police. After some incident however, he was transferred to Mishou. Those two track down offenders with special abilities who managed to get away with their crimes.