In theory the TARDIS should be able to change its appearance to blend in unobtrusively wherever it happens to materialize. In practice, however, because of a fault in the chameleon circuit, it always looks like a police box a minor inconvenience the Doctor hopes to correct.
Fixing the mechanism involves a visit to Earth and a trip to the planet Logopolis normally a quiet little place that keeps itself to itself. But on this occasion the meddling presence of the Doctor s archenemy, the Master, ensures the disruption of normality. And even the Master is horrified by the threat of total chaos he unintentionally precipitates until he finds a way to turn the imminent destruction of the universe to his own advantage "
