"Can't Stop This Thing We Started" is the fourth episode of the fourth season of One Tree Hill and the 71st produced episode of the series. It was broadcasted on October 18, 2006. Peyton introduces hip-hop sensation Lupe Fiasco at Tric, while rumors that Brooke is pregnant run rampant. Still dealing with their car accident, Nathan buys a motorcycle despite Haley's reservations, and Rachel poses for Maxim magazine. Meanwhile, Lucas clashes with Derek, and Deb double-crosses Karen.