'Doctor Who' trailer introduces the new companion

There’s a new trailer for the 10th season of Doctor Who, which highlights new companion Bill Potts (Pearl Mackie). “The first time you meet him, he’s funny,” she says in the footage. “The second time, he’s amazing. The third time, you realize he’s the most dangerous man in the universe.” The season marks the last for Peter Capaldi’s 12th Doctor, who exits the series this year along with longtime showrunner Steven Moffat. The new season premieres Saturday, April 15 on BBC America followed by the series premiere of the Doctor Who spin-off Class