The Vampire Diaries - History Repeating

Bonnie and Caroline took a backseat to Vicki for a few prior to 162 Candles, and History Repeating truly gives them a launching pad for their own arcs. Bonnie is receiving visions from an ancestor, Emily. Emily was Katherine's servant, and then the burning church back story involving her and the demise of vampires (except Stefan and Damon) is further elaborated.

Damon loved Katherine and his return to Mystic Falls involves her "release". Not just gets but those of her kind not quite burned alive as oft-reported. A deal was made between Emily and Damon regarding Katherine's "safety". Emily, taking possession of Bonnie after an ill-advised seance (recommended by Caroline after a talk about witches and hauntings), at Elena's, reneges on the deal, with Damon unable to stop her. Later on in the episode, The Turning Point, Logan also mentions to Damon that the one that turned him was interested in finding Katherine. Logan is put down by Alaric. Denied Katherine twice, Damon seems so close yet never enough to regain his lost love. He is prepared to turn the vampires loose on Mystic Falls but Stefan thankfully is there to upend him.

Damon tells Caroline she's shallow and has little value. This stemming from her inability in getting the talisman from Bonnie. She takes it to heart. Matt finds her wasted and pitiable, needing a friend. He takes her home, Caroline's drunk, immobile body with mom's permission, and lies with her in bed, innocently, over the night. The two eventually talk the next day, after awkward exchanges. He tells Tyler, who spotted them flirtatious in the high school hall, that he does like her​. So this new romantic subplot emerges.

So Damon is tied inexorably to both girls' stories, in one way or another. Damon is often involved in every character's story, but as the first season continues not every single action is egregious. Just most of them.