Character development drawing, I guess?
What ran through my head while drawing this is that Monty's older brother, whom he idolizes, is throwing a party while their parents are out of town. Believing he will be hanging out with his brother and the other "cool kids", Monty enthusiastically abets.
Once the party starts, however, Monty is ignored and neglected, and is pressured into drinking as a joke by some of his brother's friends. After they lose interest, he's left confused, lonely, and intoxicated.