ique ▁shop , ▁owned ▁by ▁a ▁Mr ▁Finn ist on , ▁who ▁tells ▁them ▁about ▁a ▁secret ▁passage ▁from ▁Finn ist on ▁Castle ▁to ▁an ▁old ▁chap el ▁and ▁cell ars ▁where ▁royal ▁tre asure ▁might ▁be ▁hidden . ▁The ▁girls ▁excited ly ▁reve al ▁the ▁news ▁to ▁the ▁boys ▁and ▁the ▁tw ins . ▁T ogether , ▁they ▁plan ▁to ▁h unt ▁for ▁the ▁cell ars ▁on ▁the ▁farm . ▁They ▁come ▁across ▁the ▁castle ' s ▁kitchen ▁m idden ▁and ▁realize ▁they ▁are ▁close ▁to ▁finding ▁the ▁tre asure . ▁▁ ▁Junior ▁sp ies ▁on ▁them ▁and ▁r ush es ▁to ▁break ▁the ▁news ▁to ▁his ▁father ▁and ▁his ▁father ' s ▁friend ▁Mr ▁D url eston , ▁who ▁decide ▁to ▁exc av ate ▁the ▁castle ▁site , ▁find ▁the ▁fortune ▁and ▁sell ▁the ▁goods ▁in ▁America . ▁Mr ▁and ▁Mrs ▁Phil pot ▁consent ▁to ▁the ▁exc av ation , ▁much ▁to ▁the ▁dis may ▁of ▁the ▁children . ▁The ▁children ▁dig ▁around ▁the ▁site , ▁hoping ▁to ▁beat ▁the ▁men ▁in ▁finding ▁the ▁tre asure . ▁Initial ly ▁they ▁are ▁un success ful ▁but ▁the ▁tw in ' s ▁dog ▁S ni ppet ▁and ▁their ▁jack da w ▁N ose y ▁lead ▁them ▁to ▁a ▁bur row , ▁beneath ▁which ▁the ▁secret ▁passage ▁st ret ches ▁out . ▁ ▁The ▁children ▁discover ▁the ▁cell ars ▁and ▁the ▁tre asure , ▁only ▁to ▁become ▁tra pped ▁inside ▁the ▁tunnel ▁when ▁the ▁entrance ▁c aves ▁in . ▁They ▁take ▁another ▁way ▁and