With　a　word　of　excuse　to　Lady　Tamplin；　he　broke　it　open；　and　an　expression　of　utter　astonishment　came　over　his　face　as　he　read；　then　he　looked　at　his　hostess。

〃This　is　most　extraordinary。　I　say；　Rosalie；　I　am　afraid　I　will　have　to　leave　you。　The　Prefect　of　Police　wants　to　see　me　at　once。　I　can't　think　what　about。〃

〃Your　sins　have　found　you　out；〃　remarked　Lenox。

〃They　must　have；〃　said　Derek；　〃probably　some　idiotic　nonsense；　but　I　suppose　I　shall　have　to　push　off　to　the　Prefecture。　How　dare　the　old　boy　rout　me　out　from　dinner？　It　ought　to　be　something　deadly　serious　to　justify　that；〃　and　he　laughed　as　he　pushed　back　his　chair　and　rose　to　leave　the　room。

Chapter　13

VAN　ALDIN　GETS　A　TELEGRAM

On　the　afternoon　of　the　15th　February　a　thick　yellow　fog　had　settled　down　on　London。

Rufus　Van　Aldin　was　in　his　suite　at　the　Savoy　and　was　making　the　most　of　the　atmospheric　conditions　by　working　double　time。　Knighton　was　overjoyed。　He　had　found　it　difficult　of　late　to　get　his　employer　to　concentrate　on　the　matters　in　hand。　When　he　had　ventured　to　urge　certain　courses；　Van　Aldin　had　put　him　off　with　a　curt　word。　But　now　Van　Aldin　seemed　to　be　throwing　himself　into　work　with　redoubled　energy；　and　the　secretary　made　the　most　of　his　opportunities。　Always　tactful；　he　plied　the　spur　so　unobtrusively　that　Van　Aldin　never　suspected　it。

Yet　in　the　middle　of　this　absorption　in　business　matters；　one　little　fact　lay　at　the　back　of　Van　Aldin's　mind。　A　chance　remark　of　Knighton's；　uttered　by　the　secretary　in　all　unconsciousness；　had　given　rise　to　it。　It　now　festered　unseen；　gradually　reaching　further　and　further　forward　into　Van　Aldin's　consciousness；　until　at　last；　in　spite　of　himself　he　had　to　yield　to　its　insistence。

He　listened　t