You decide you need to make your costume first

From Create Your Own Story

Putting the letter on the table, you decide you need to finish your costume. Sewing the gloves to the Green Metal jacket and fitting the helmet on top, it already looks like master chief at this rate. Your tongue pokes out of your mouth as you fit the other shoulder pad onto it. This goes on for hours and you completely lose track of time.

"What are you doing?" For a moment you just sit there, attached nuts and bolts to your fake Machinegun. Then you do a double take and realise Luna is in the room. "Um... I totally forgot! Sorry! Don't hang me!" Luna just looks at you with a mad expression. "I won't hang you..." Then her expression changes. "Ugh. Night court. BE THERE TOMMOROW AT NOON." And with that, she vanishes.

Decide the costume looks good enough so far and go to sleep.