The BBC has released the synopsis for The Pilot, the first episode of Series 10:
Two worlds collide when the Doctor meets Bill. A chance encounter with a girl with a star in her eye leads to a terrifying chase across time and space.
Bill’s mind is opened to a Universe that is bigger and more exciting than she could possibly have imagined – but who is the Doctor, and what is his secret mission with Nardole on Earth?To be broadcast Saturday 15 April on BBC One, the time has yet to be confirmed.
— Doctor Who Official (@bbcdoctorwho) March 30, 2017