Since the Water Cavern has that one-way dive down a waterfall in its second leg, you have to use the hovercraft to get back to Kaipo.
Final Fantasy IV DS Music - Theme of LoveFinally! A character death we get to narrowly avert in a Final Fantasy game! I bet Josef is totally jealous.
Rosa: You're alive! Thank goodness!
Cecil: How do you feel?
Rosa: I'm fine. But I thought I'd lost you. They told me you died in Mist when the earthquake hit.
Cecil: I'm sorry to have put you through all that... Rosa, who is Golbez?
Rosa: He's the new captain of the Red Wings, appointed by the king himself. But the king has been acting... strangely. I believe Golbez is manipulating him to collect the Crystals for himself. With Mysidia's Water Crystal in hand, he'll surely go after the others, which are the Fire Crystal of Damcyan, the Wind Crystal of Fabul, and the Earth Crystal of Troia.
Edward: The Fire Crystal has already fallen into his hands.
Cecil: Ah, let me introduce you. Edward is the prince of Damcyan. Rydia is a summoner from Mist. I wouldn't have been able to get the Sand Ruby and cure your fever without their help.
Rydia: Hi there.
Rosa: Hello, Rydia. Thank you both so much. Cecil, after Damcyan, Fabul must be their next target. We must... *cough cough*
Cecil: You have to rest now. Don't worry. We'll go to Fabul.
Edward: But to reach Fabul, we must traverse Mt. Hobs, and the trail is blocked by thick ice.
Rosa: Rydia, can you cast Fire?
Rydia: ...No.
It's true, she can't. Tellah had Fire, Blizzard, and Thunder magic; Rydia has only Blizzard and Thunder.
Rosa: Fire is the most elementary of black magic spells. As a summoner, you... *cough cough*
Cecil: Rosa, stop! You're not coming with us in that condition!
Rosa: I'll be alright, really. As a white mage, I promise I won't be a burden.
Edward: Rosa only wishes to be with you, Cecil.
Cecil: ...Alright. We'll go together. Make sure you get plenty of rest tonight.
Rosa: I thank you.
Rosa is a white mage, one of the few jobs to have its roots in the first Final Fantasy game rather than the third. She's better at archery than those guys(?), though, with an Aim ability that increases her accuracy and damage with bows and arrows to supplement her healing and protective magic.