I'm pretty sure my Mom and Lizzie know something is wrong, despite my best efforts. I've spent the last three days crying almost non-stop, so my face is puffy in a way that makeup can't hope to hide.

Lizzie didn't even comment that I didn't spend the night at Derek's with her last night like she asked me to. I know she was disappointed, so the fact that she didn't say anything means it's obvious to her that something's wrong.

We're eating lunch on campus at the student center food court. I'm holding a sleeping Simon. Everything feels a little bit better with him in my arms. He's perfectly precious. His skin is so clear and smooth, it's practically translucent. His breath comes in fast little puffs and I can feel his rapid heartbeat under my hands.

I tried so hard not to let myself think through the convoluted path of what our kids' relationship to Simon would be. He'd be their half uncle on both sides. I think there have been weirder relationships. Sometimes, in the darkness of night, in the cocoon of Derek's arms, it seemed… almost possible. But the harsh reality of daylight burned away the fantasy.

It's over now.

My eyes start to water again and I pull Simon in a little closer and breathe the smell of his sweet head.

"Casey," my mom cuts through Marti and Lizzie's argument about the merits of plastic forks. "How are classes going? You doing okay with the workload?"

"Yeah," I say brightly. I'm not thinking about Derek's intervention. I'm not remembering the way he climbed into my bed. I'm not I'm not I'm not. "Classes are great! I'm learning so much!"

"That's great honey," she says. There's a pause and she exchanges a look with Lizzie. "Any boys that you're interested in?"

I flinch. "Nope!" I say, my voice is high and shrill even to my own ears.

Lizzie and my mom are giving each other significant looks again.

"Casey, can I come hang out with you in the dorms for a little while?" Lizzie asks.

"That's a great idea," Mom answers before I can. "The rest of us should go to the bookstore and grab some Queens gear to wear to Derek's game tomorrow!"

"I want to go to Casey's dorm too," Edwin cuts in. "I gotta check out what the college living sitch is like."

There's a slight scuffle sound and he winces suddenly. "Ouch! Lizzie, why'd you kick me?"

"Don't you want to get a Queens shirt to wear for the game tomorrow?" She's glaring daggers at him. My sister is not subtle. I wonder if I'm that bad.

"Yes Edwin," my mom says forcefully. "You should come with us."

"But I want to go to Casey's dorm!" Edwin is even more clueless than Derek.

I don't want to be alone with Lizzie, as she's clearly angling for. She and my mom obviously think that I don't want to talk about it in front of the whole family and are trying to give me and Lizzie space to talk. But I can't talk through the disaster that is my love life with Lizzie like usual. The thought of her probing and actually figuring out what's wrong is terrifying. The thought of her reporting back to Mom is unthinkable.

"Yeah Edwin," I say enthusiastically. "You have to see the dorms!"

Sarah is in our room when I bring Lizzie and Edwin back. I freeze in the doorway. I still haven't told her that Derek is my step brother. I talked around it when I told her about the break up. I thought it didn't matter anymore, and why go through the drama of telling her, if we're not together anyway?

The second I see her, I realize what a colossal mistake I've made.

"Hey!" I say. "Um, this is my sister Lizzie and my step brother Edwin."

She smiles at them but her brow wrinkles in confusion. "Oh! So nice to meet you guys! I've heard so much about you both! Are you guys here to see Derek's game tomorrow too?"

I stare at her with wide eyes and shake my head slightly, trying to convey a "stop talking" message. Oh god, why didn't I tell her? In my worst case scenarios, I thought she would find out from the family that we're step siblings. It didn't occur to me that it could be the other way around.

I clearly did not think it through. She thinks Derek and I have two separate families. That both came to see Derek play. Because we've told her over and over again that our families are really close.

Lizzie frowns slightly, confused by her wording. Edwin responds with a smile, "Yeah! We couldn't miss Derek's big game! Our parents even let us leave school early yesterday so we could make the drive!"

"So fun!" Sarah smiles at his enthusiasm. "Did you drive up with Derek's family?"

"We should meet up with everyone at the bookstore!" I shout really loudly at the same time.

Lizzie is frozen in place. Her eyes are huge as she stares at me.

Edwin looks at me, confused by my shouting. "I don't think they're expecting us yet. I still want to tour the dorm." He turns to Sarah. "What do you mean? We are Derek's family."

Sarah's brow is wrinkled in confusion as she processes Edwin's statement. I see the second she figures it out. Her brows pop up in shocked surprise. "Oh, right!" she says. "Of course, I don't know why I said that."

She and Lizzie eye each other.

This is my worst nightmare. They both know. They both, very obviously know. My sister knows.

Edwin is still frowning. He's not as sharp as Lizzie but I can tell he's piecing it together.

"Let's start the tour!" I yell desperately. "Do you want to see the common room?"

"Did you not know Casey and Derek are step-siblings?" Edwin asks.

Lizzie elbows him hard. "Shutup!" she whispers.

"Ouch," he winces. He looks confused, and opens his mouth to speak again, but glances at Lizzie and doesn't say anything.

Sarah's eyes are huge and there's a flush on her cheeks. "I think it slipped my mind," she said. "I'm sure Casey told me, but I'm not close to Derek so I just forgot." She mumbles towards the end and looks at the floor.

At least I know she's never lied to me before. She's terrible at it.

"Let me show you around the dorm!" She says, too loudly. "The basement is um. Really cool!" She tries to lead the way out of our room.

I can't tell what she's thinking. Does she think it's disgusting and she's waiting for my siblings to leave before she tells me how gross and wrong it is? Or is she just surprised? I've wondered so many times over the last month how she would react if I just told her.

I'm relieved that whatever else she thinks, she's trying to cover for me. I think it means that she's still my friend.

Edwin and Lizzie don't move to follow her. They're exchanging looks. They must have some sort of secret eyebrow language, because all of a sudden Edwin gets it too.

He lets out a gasp and whips his head around to look at me with his mouth open. He looks back at Lizzie. "Is it… finally… is it what we thought?"

What they thought? What did they think?

Lizzie nods and makes a shushing gesture at him.

"I'd better get going. I have some studying to do," Sarah says awkwardly. She gives me a sympathetic look as she leaves the room and mouths "sorry."

Definitely still my friend. If I weren't so upset about Lizzie and possibly Edwin figuring it out, I'd be relieved that she finally knows. Whatever she has to say to me, when we can eventually talk about this, I don't think it'll be too bad. If only I'd told her this whole thing could've been avoided. Why am I so stupid?

The second the door closes behind Sarah, Lizzie turns to me with her brows raised and arms crossed.

"Edwin, would you like to tour the dorm now?" I ask desperately.

"No way," Lizzie says firmly. "We could've had this conversation in private, but you insisted he come with us. He knows now anyway."

"Nothing to know!" I squeak. "She just forgot Derek and I are step siblings. Like she said!"

"Casey!" Lizzie says, rolling her eyes at me. "Start talking. It's obvious you need our help anyway. You're both miserable and avoiding each other."

I stare at her, open mouthed. Maybe she doesn't know? I never imagined her reacting this way, if she ever found out. With this sort of aggrieved nonchalance, as though this is just another argument between me and Derek that she and Edwin have to negotiate for us.

"Just to be clear," Edwin butts in. "We're talking about you and Derek. Together. Romantically." He states it matter of factly. Edwin Venturi, the businessman, laying out the facts.

I can't get over it. They're not surprised? Upset? Grossed out? Shaken to their cores that the platonic sibling rivalry we had was all an illusion?

They're just… standing there. Staring me down, waiting for answers.

I suddenly wish Derek were here, and not just because I miss him and want us back, but because it's not fair that I have to face this alone. I thought about and dreaded our family finding out, I imagined how it would all go badly, but I never thought I'd have to do it by myself. I thought it would at least be the two of us together, a united front.

"What do you want to know?" I sigh.