Take Frank to the party.

"Thanks dude. You rule. I'll go get a car. Thanks for driving too. You just saved my drunk ass tonight." Frank says
"Sure, just get some breath mint while your in the car," you say
"Ahh shut up," he says smiling.

You return to Katherine with her drink and tell Kat about the party. You also tell her about Frank needing a ride.
To your surprise she not upset.
"The beach house may be fun," Kat says. "Plus I think it nice that you would help out your friend"
"Thanks. You're the best," you say.
"Yeah I know. I'm the bomb," she joke

So you dance for a bit longer until Frank returns with a car. You drive while your buddy Frank sleeps in the back seat. Your senses come alive when Kat places her hand on your upper thigh. The feeling is amazing. It is getting really dark as you drive off into the night. Some girl band is playing on the radio. Kat still has her nice dress on as neither of you had a chance to change. You arrive at the beach house and to your surprise Frank was telling the truth. The place is huge. It's like a mini mansion. There are sounds of music coming out of it and you see some empty beer cans on the ground. There are plenty cars and motorcycles parked near the house. The house is three floors and very well furnished. It looks a page from an Ikea catalogue. There is a big TV playing kung-fu flicks that seems to match with the hyper music.

You head inside the party and there are people dancing everywhere. People are making out all over the place. You can see people on the beach swimming in the night seas. You also see a bunch of surfers using some herbal medicine by the shore. One of the stoners is a girl you know named Hayley. She's cool and all but a bit of a pothead. She is quite pretty though. All and all a happening party

"So what you want to do?" Kat asks you as you wonder around.

You think that you could dance, talk head out on the beach or do any number of things.

Frank interrupts as he hasn't yet taken the hint to leave you and Katherine alone now, "there are extra surf boards if you want them. The guy here runs a surf store. Also we're are barbecuing outside. There's some nice steaks being cooked. Plenty of beer too."