- Bess Marvin:Bess is a little boy crazy, but she's great with people and can talk people into anything! With an awesome fashion sense and a cheery disposition, she can be coaxed into helping Nancy on a case. But when Bess is kidnapped on Dread Isle, she'll need Nancy's help to escape.
- George Fayne: one of Nancy's best friend and Bess' cousin. She is sensible and matter-of-fact about life. She is the one who remembers the small details and is the best with technology. On Dread Isle, she feels helpless when Bess is kidnapped and is trying to fix a satellite phone.
- Johnny Rolle- Johnny is stuck on Dread Isle since monkeys trashed his boat, and can't leave until the repairs are finished. Since he's been on the island longer than Nancy and George, perhaps he can help find Bess... or was he the one who kidnapped her in the first place?
Coucou- Coucou is a smart-talking, yellow-headed Amazon parrot. She seems to be related to the parrot Loulou from the game The Curse of Blackmoor Manor,whom she calls " Great Grandma Loulou". Coucou can hear the secrets people whisper, but won't tell unless you give her a treat!
The Gibsons- The Gibsons are the couple who own the resort where Nancy, George and Bess are staying. George suspects that they are the kidnappers because the map found in the diving supply closet seems to show that they have been tracking Nancy's movements.Are George's suspicions true?
Nancy and her best friends Bess and George travel to the Bahamas for a vacation when Bess is suddenly kidnapped and held for ransom. Players assume the role of either Nancy or George, depending on the scene, as they search for the missing artifact from the "Seven Virtues" fleet that wil rescue Bess from kidnappers. During the quest for the lost treasure, players will immerse themselves in diving, sailing, and interacting with wildlife in the Bahamas. They will also decrypt a riddle book, unlock treasure chests, and explore dangerous underwater shipwrecks.
- Take a side trip into the sand/bushes on the south side of the island on your golf cart to get a pirate cat easter egg.
- This is the first ND game where you meet Bess and George in person.
- In the lobby of the hotel, you meet Coucou, who is actually the great granddaughter of Loulou, the old parrot in Curse of Blackmoor Manor.
- Sonny Joon is one of the staff for the monkey research facility. SJ is mentioned in several other ND games.
- El Toro means The Bull in Spanish
- If you find pieces of paper in the bottles while sailing, they will be automatically pieced together to form a passage from "The Raven" by Edgar Allan Poe, the one just before the raven appears. Certain letters in red will tell you to go to and dive to one of the sunken ships where the sharks are, and, using the metal detectore from Johnny Rolle, you will find an Easter Egg. This is also a reference of the next game, Warnings at Waverly Place, as Corine mentions that she is a Poe fan, as well as Leela having the missing Poe book, "The Black Cat and Other Stories", which includes "The Raven" and other works, as well as the pendulum challenge, a reference of "The Pit and The Pendulum".
- When Nancy sails to the isolated island, in the corner of the screen, you can see the rocket from The Haunting of Castle Malloy.