The missing slice

Take Andre's part first, then Ayumi's. Ayumi is suspicious and sharp; Andre is honestly confused, then a little hurt. Copy his surprised "Wait. Are you accusing me of stealing your cake?" and the teasing tone in his last two lines.

1. AyumiAndre, did you eat my cake?
2. AndreWhat cake?
3. AyumiThe last slice of my birthday cake. It was in the fridge, with a note. "Ayumi's. Don't touch."
4. AndreI didn't touch it. I don't even like chocolate.
5. AyumiThen why is there a plate in the sink with crumbs on it?
6. AndreThat's my plate. From my toast this morning.
7. AyumiToast crumbs look very similar to cake crumbs, Andre.
8. AndreWait. Are you accusing me of stealing your cake?
9. AyumiYou're the only other person who lives here. Who else could it be?
10. AndreI don't know. But I'm not the one who did it. Honestly.
11. AyumiHmm. You did eat my noodles last month.
12. AndreAnd I replaced them the same day. With better noodles.
13. AyumiThat's true. Okay, I'll give you the benefit of the doubt. For now.
14. AndreThank you. Did anyone else come over yesterday?
15. AyumiOnly my sister. She stayed until... oh. (phone buzzes)
16. AndreWhat does it say?
17. AyumiIt's from her. "Sorry, I ate your cake. It was calling my name. Buying you another."
18. AndreSo the thief was your sister. And you pointed the finger at me.
19. AyumiI'm sorry, Andre. Really. I'll buy you coffee to make up for it.
20. AndreCoffee and half of the new cake. Even though I don't like chocolate.