HELP: I can’t remember the name of the Japanese drama.

I think it was released in the 2010s, maybe more than 15 years ago. The story is about a girl who practices kendo and meets a new transfer student from an elite school (possibly MIT). Together, they start solving mysteries. I remember one episode where the female lead was transported to the past and solved a case with a man who looked just like the transfer student from her school. In that episode, she also lost her phone in the past.