you talk to them do a random mission and then you see only 1 of them then you do anouth random mission and you will see no1 at the pond then go to the board full of rescue mission and theirs one for wish cave:]
ps be careful it makes your team lvl 1 and if you die with wish stone dont worrie you can get anouther onein wish cave but i forget wich floors its on well team killers OUT!