Spencer is Topanga's twin sister, you don't look alike and have completely different personalities and attitudes.
Topanga is a smart, caring, striaght-A student who follows every rule. You are more edgy, have straight C's and B's, and is very quiet.
That's why Cory and Shawn are the only people who know you're related to Topanga.
You are dating Shawn and Topanga is dating Cory.
Originally today, Shawn was supposed to go to your house while Topanga goes to Cory's, but your parents plans changed and they know that you and Shawn love each other and tend to get handsy, so the two of you had to go to Cory's house because your mom didn't trust you home alone.
"Hey. Hope you don't mind, I had to bring my sister" Topanga said, kissing Cory's cheek as you walked inside
"Yeah, Shawn told me." Cory says with a sigh.
Shawn is sitting on the couch when you arrive, so you go and sit with him, and Cory and Topanga sit together.
Cory and Topanga always yells at you for cussing and vaping, but you don't really care.
