In the present, Stefan is consumed by guilt over his past actions and his recent relapse into human blood consumption. He attempts to commit suicide by taking off his sun-protecting ring and waiting for the sun to rise, but Elena eventually convinces him that his life is still worth living. John Gilbert’s Agenda:
Through flashbacks to 1864, viewers learn that the brothers were shot by their own father, Giuseppe Salvatore, while trying to rescue Katherine Pierce from being taken to the church to be burned.
: Stefan wakes in transition and accidentally kills his father during a struggle. The smell of his father's blood triggers his predatory instincts, causing him to feed and complete his transformation.
Analysis of Narrative Turning Point: The Vampire Diaries – Season 1, Episode 20, “Blood Brothers”