Professor Seta goes on a dig and falls into a deep hole.  Meanwhile Keitaro is keeping Sarah at the Hinata Inn for him.  She acts all sweet around Naru while torturing Keitaro in private.  Naru finally gets wise to her.  When all the other girls meet her she runs off and they all follow after.  They stop at the doors to a supposedly cursed place.  Suddenly the doors burst open and Seta steps out.  Now Naru knows about his return and Keitaro puts two and two together - or so he thinks - about her crush on him.  Later they all go into the caves in search of the lost turtle worshiping civilization when strange mecha turles start chasing everyone.  Motoko accidentally brings down the roof and traps them there.  Faced with possible death Keitaro makes a bold announcement...