This series follows in the same time slot as Detective Conan - Kudo Shinichi e no Chousenjou and it offers the same format: a mystery or crime to be solved in half an hour without too much reliance on intricate plots or clever deduction. In fact, so far a lot of the crimes have been solved by using a voice manipulator and some martial arts.
Chiaki Kuriyama stars as the ex-spy who is persuaded by her ex-boss to work for her as an undercover agent investigating criminal activity. All the while, she's trying to keep this a secret from her husband and child who have no idea that she's anything other than a doting housewife.
As you'd expect from a J-drama, the main story is just being hinted at in the first few episodes. There are occasional references to her boss having a hidden motive for hiring her again, and that she is being targeted by some dark, mysterious organisation. And perhaps even her family is under threat.
Chiaki adds a bit of big-screen glamour to a fun but otherwise unremarkable series. She's certainly very watchable and she handles the martial arts sections very well. The trouble is that everyone else seems a bit anonymous next to her. Since she's the one that looks after the family/goes undercover/solves the crime, no one else has much screen-time to establish a character.
I'll be honest, I don't expect this series to surprise me. I'm pretty sure that somebody will try to kidnap her son. Similarly, her boss will double-cross her before he sees the error of his ways and helps her right at the end. If this show can avoid either of these two cliches, it will have done better than my expectations. In the meantime, I'm enjoying watching it for what it is: some lightweight crime-solving with a little action sprinkled on top.