After a fight Hayate, Nagi heads to the apartment complex to hang out.  But her “little sister” is the only one home.  This might be Nagi’s chance to find out what Ruri’s real goal is. 
Why should I become your butler?
¿Eh? ¿Por qué me convertiría 
en tu mayordomo?
¡¿Y por qué iba yo a aceptar algo así?!
Por que eu vou 
ser o seu mordomo?