Presumably talking about Stefan, Elena, Damon and Alaric are wearing serious looks despite celebrating Elena's 18th birthday.
Elena, Damon and Alaric are found in the first official picture of "The Vampire Diaries" season 3. Taken from the season premiere, the scene takes place outside with the three of them seriously discussing something during Elena's birthday party.
In "The Birthday", Elena turns 18 and her friend Caroline insists on throwing her a party at the Salvatores' mansion. "There will be a small time jump [from where last season ended] as we celebrate Elena's birthday," executive producer Julie Plec told TV Guide. "But as is the pattern in Mystic Falls, the event never reaches its climax."
Speaking of Damon's present to Elena, Ian Somerhalder told Zap2It, "She refuses to let him buy her anything, so he doesn't technically give her anything for her birthday. But he came across something that she really, really, really wanted and needed, and he did what he had to do to get it for her. She thinks that he stole it, or that he found it. It's a very beautiful moment between them. It's a really sweet, quiet moment."
Throughout the season which premieres September 15 on The CW, Elena would also be battling her attraction towards Damon.