This scene took place in my story called Lisa's adventures at the Wonderplant, where Lisa was forced to work at the nuclear station under control of mr. Burns. Bart saved Lisa from Burns mansion and Lisa told him truth about her humiliating position.
At that point Bart's life is a complete mess, he broke up with some of his girlfriends, lost some of his jobs, he's not okay. With Lisa they become closer to each other after he learned her secret and here she just trying to comfort him when he got some bad news.
Барт: Ты в курсе, что на тебя дым идет?