As celebration for Percy retrieving Zeus' lightning bolt they threw a huge party for him.

Luke and you weren't on the best terms, after a messy break up. At the party though some of the Dionysus kids sneaked in some alcohol.

They mixed the alcohol with the juice they were giving out and Luke was downing those drinks. So he became drunk very fast.

Luke's siblings didn't know what to do with Luke since he was a clingy mess so they decided to bring him to you.