In Soerabaja, an Indonesian whose life Captain Boll once saved reveals that legendary diamonds from the sunken ship Pieterzoon were salvaged by native divers, and Boll is directed to a Chinese junk captain who has "cargo" that will lead him to the diamonds. The "cargo," Boll discovers, is a woman named Kim Kim, a dancer from the sultan's palace who was taken as a slave by the Chinese. Boll buys her and smuggles her onto his ship, risking slavery charges when his first mate, Flint, discovers her and blackmails him for half of the fortune.