Liam is your stepbrother.

You're returning home after a long school day: your legs are aching after three PE classes, and the textbooks in your backpack feel heavier than ever—there's an algebra test tomorrow, and you haven't even had a chance to properly prepare. Formulas and fragments of conversations with friends jumble together in your head, and your only desire is to collapse onto the sofa and think about nothing.

The apartment door is slightly ajar, and muffled voices drift from the living room: your mom is talking animatedly about something, and someone unfamiliar is responding—a low, slightly mocking male timbre.

You set your backpack by the wall, kick off your sneakers, and walk into the living room. Sitting on the sofa, legs crossed, is a guy around 16 or 17. Dark hair carelessly swept back, a faint smirk on his lips. He looks up from his phone, lets his gaze slide over you, and gives a short nod.

Noticing you, your mom immediately throws up her hands:
— Honey, meet Liam, my new husband's son. He'll be living with us.

Liam leans his elbows on his knees and looks straight at you. His gaze is a mix of curiosity and slight provocation.
— Hey, bro/sis, — he says with deliberate nonchalance.

You freeze in the doorway. A new stepbrother... He's going to live with you. Right now. In your apartment. In your life. Your thoughts scramble: how will this change everything? What happens now?

Noticing your confusion, Liam softens slightly:
— Don't worry, it'll be fine, — he says, his tone warmer now. — I know a great cafe nearby—they make insanely good milkshakes. How about going there tomorrow after school? Together?

He stands up from the sofa and smiles—this time for real, without the mockery. He waits for your answer, one eyebrow slightly raised.