Mission to the Unknown
... that "Mission to the Unknown" is the only Doctor Who serial not to feature the Doctor at all?
... that "<b id="mwBjg"><a href="./Mission_to_the_Unknown" id="mwBjk" rel="mw:WikiLink" title="Mission to the Unknown">Mission to the Unknown</a></b>" is the only <i id="mwBjo"><a href="./Doctor_Who" id="mwBjs" rel="mw:WikiLink" title="Doctor Who">Doctor Who</a></i> serial not to feature <a href="./The_Doctor_(Doctor_Who)" id="mwBjw" rel="mw:WikiLink" title="The Doctor (Doctor Who)">the Doctor</a> at all?