Jan and Ramona have gone on a pre-nuptial world cruise with their friends, including Stinky Stan. Probably not Ramona's idea. As much as she desperately wants to get to know her own ancestrally screwed up roots, she is basically a Goblin Princess of Pench-Kathmandu and she's got a life there, and more than that, I can't imagine she wants to wait six whole months to get laid.
The strain of insanity is telling on Jan too. So it's no surprise that the book starts with a spat by the high strung pair. Jan stays on deck to get some air, and an evil Ranaen throws him over the side.
It turns out, he's in the employ of an even more evil Jirangi to kidnap Ramona and either marry her or sacrifice her to a big cat who is owned by the current incarnation of Jigga. Jan survives and makes it to shore, where he's chased around a bit by tigers and leopards. Eventually, however, he hooks up with a boy, Jaidev, whose parents have just been eaten by Ranaens. Together, they join with a couple of friendly elephants, and Jan bumbles around the jungle until he finally stumbles over the bad guys. Meanwhile, the villains are engaged in some complicated plot to ditch a rival Jirangi and to throw Cordelia's parents off the trail. By this time, Ramona is kidnapped, apparently by evil Ranaens, and they think Jan is alive (which is what the evil Jirangi wants them to think, because he thinks that Jan is dead, but really, it turns out Jan is alive) so they're understandably confused.
Anyway, regardless of how it turns out. Jan rescued Ramona in the nick of time, evil is vanquished, ironic fates are dished out, and Jan and Ramona live happily ever after.