From the Back of the Book:
YOU are the only hope for the salvation of the Doctor in SEARCH FOR THE DOCTOR
The year is 2056. From the Fern Spacelab orbiting above the Fusion Energy Research Network in California, OMEGA has mounted a devastating attack.
OMEGA plans to take over the Doctor's mind and body. By controlling the Doctor's awesome power, OMEGA can take revenge on the Time Lords, who sacrificed him to obtain the secret of Time Travel.