We’ve got the where and when on the fourth season of “Doctor Who.” Sci Fi Channel will air the BBC hit, scheduled to begin in April. Sci Fi will also air the spinoff series “The Sarah Jane Adventures.”

“Sarah Jane” is written and produced by the same creative team behind “Doctor Who.” The series centers on Sarah Jane Smith (Elisabeth Sladen), former companion to the Doctor, who investigates offbeat mysteries with her young friends Maria, Luke and Clyde. On “Doctor Who,” David Tennant returns as the 10th Time Lord, joined by a new companion, Donna Noble (Catherine Tate), who reprises her role from the previous Christmas special. The Doctor’s previous companion, Martha Jones (Freema Agyeman), comes back in midseason.