Moon Child follows a group of childhood friends as they advance in a futuristic criminal underworld. Sho feels he is doomed to walk in his idol Kei's footsteps as a vampire with the gift of eternal life and the curse of blood thirst. Over time, their tight friendship becomes corrupted because of their rivalry and love for the same woman.

Sai, a young artist living in a downtown warehouse delves into an ancient world of blood and lust. An enigmatic foreigner seduces her to try a long forgotten drug making her the prey of a dimensional vampire who needs her new found hunger for blood to cross over from his world to hers.

Handsome young vampire Billy (Andre Frauenstein) seems to have finally found his true love in Jenny Shapiro (Rikki Brest), a beautiful young woman he meets at a nightclub. Despite efforts by those around them to keep the two apart, including Billy's past love Lisa (Christina Storm), they appear to be destined for one another. Their happiness is suddenly cut short when a scientist researching a treatment for HIV/AIDS accidentally discovers a serum that will allow vampires to walk in the daylight with humans. This leads to an all-out war between vampires; those who are against the serum and those who would use it to leave the shadows of night, including vicious upstart vampire Borlak (David James) who will stop at nothing to obtain it. Billy and police detective Joe Kau must now work together to protect Jenny and her family, and to keep this discovery from those who would use it against all of humanity