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. 
...the Sanzenin household's treasure...
el tesoro de la familia Sanzenin...
el tesoro de la familia Sanzenin...
...tesouro da família Sanzen'in...