Alexander is first introduced to the story as the assistant to Dr. Deep on his ship, The Cassandra. While claiming to be a science student, he does a lot of the heavy work on the boat and also serves as the ship's cook, despite not being very good. Alexander and Dr. D get a request from a pair of zoo owners to find a real life mermaid, with an offer of a one million dollar reward for its capture. Dr. D. agrees to search for the mermaids, but has reservations over putting the mermaid in captivity. Not too long after, Billy Deep finds a young mermaid girl, and the group manage to capture her, placing her in a giant fish tank.
A few nights later, Billy and his sister Sheena awaken to see Dr. D unconscious and surrounded by masked men. They hope that Alexander can help, but it's soon revealed that Alexander was in collusion with the masked men the entire time. Alexander reveals that he was seeking the mermaid to give to his bosses for a twenty million dollar reward. Alexander and the kidnappers place the Deeps in the giant tank and throw it off the boat, while they escape with the mermaid in their own boat. But before the Deeps are done for, they are rescued by the other mermaids, who are out to save their young one.
The Deep family catch up to the kidnappers, only for the kidnappers to set their dinghy on fire. They manage to put the fire out as the kidnappers plan to throw them back into the water. Suddenly, the kidnappers' boat begins to rock back and forth as the mermaids are violently shaking it, eventually freeing the young mermaid. The Deeps escape, as do the mermaids. However the status of Alexander and the other kidnappers remains unknown.
When Alexander is first introduced, he comes off as very friendly and unassuming, particularly towards Billy and Sheena. He has a love of cooking, despite everyone else finding his cooking to be pretty terrible. And even after he betrays the Deep family, he claims that he only did so because the kidnappers would have killed him as well. Although this is more than likely a facetious claim considering the fortune he intended to make after giving the mermaid to his bosses.
Alexander is described as being in his early twenties. His height is 6'4. He is very muscular and tanned with wavy blond hair, blue eyes and powerful hands. Billy states that he doesn't really look anything like a scientist due to his physique.