On their way to drive Karen home from the airport, Keith & Lucas collide with an oncoming vehicle, leaving Lucas unconscious & fighting for his life. At that moment, Dan is traveling to Deb's house to plead with her to give their marriage a chance, & he witnesses the accident. At the hospital, Dan must acknowledge that Lucas is his son in order to authorize emergency surgery. Karen is paged at the airport with the devastating news. Meanwhile, Peyton decides to tell best friend Brooke that she kissed Lucas.