Jamal sees some strange masked creatures in the park and finds a THABTO button where the masked creatures were. Also, Jamal's sister, Danitra, goes to college and leaves him her computer. On the first day he gets a weird message asking ""Where are the children, are they OK?"". Lenni Frazier, a school mate of Jamal's, is also contacted by the strange ghost-like creature. Who is this mysterious being? Meanwhile, elementary student Gaby Fernandez gets her backpack stolen on her way to school.

Jamal and Lenni learn that the mysterious being is a spirit that wants to be friends. With no memory of where it came from, they nick name it Ghostwriter. Jamal goes to see Alex Fernandez, a friend of Lenni's, to help decipher a coded message he found in his locker and in the park. Now, Ghostwriter decides to write to Alex, too.

Alex learns about Ghostwriter. Jamal and Alex figure out that the THABTOS, are who have been stealing backpacks (including Gaby's) and learn that these are the same kids Jamal saw at the park. Gaby, Alex's sister encounters the mysterious being.

The team, consisting of Jamal, Lenni, Alex, & Gaby, discover that the backpack thieves are planning a final secret ceremony. They leave a fake message in one their lockers saying that the ceremony is cancelled. Alex goes undercover as one of them but there's one problem: Alex doesn't know which code name to go by.

The team, with the help of the robbed kids, set a trap for the backpack thieves at the video arcade. After the theives are caught, the four decide to become the ""Ghostwriter Team"" and vow to try and solve mysteries.