Joe declared stoutly.
âSorry, fellows,â the chief said regretfully as they reached the road, âbut regardless of the suspicions against Sutton, I have no choice.â
Frank and Joe walked sadly back to the pine grove, mounted their motorcycles, and rode home. They ate lunch quietly, puzzling over the case.
âWhat now?â Joe asked glumly. âAll we did this morning was to get Alf in trouble.â
âGreat detectives we are!â said Frank, disgusted. âHow about walking downtown? I have another idea.â
âAbout what?â âThe Fizzle soda. Since the person who had a bottle of it was in our boatâthe bald fellow or someone elseâhe was in Bayport. Maybe he did buy some here.â
The two set off and strode briskly along the sidewalk. At the first grocery store they turned in. âDo you carry Fizzle soda?â Frank asked.
âNo, I donât.â
The young detectives went into all the drugstores, markets, and lunch counters along their way. Always they asked the same question, and received the same answer. Nobody sold Fizzle soda.
At last they entered a downtown sweetshop which was a meeting place for many of their friends. âHi!â called Tony Prito from a booth where he was seated with Jerry Gilroy.
âHello, fellows,â Frank greeted them. âWeâll be over in a minute.â
Meanwhile, he asked the soda clerk about Fizzle, but received a negative answer. âOnly place Iâve ever seen it anywhere around these parts is Northport. I live near there.â
Northport again!
Frank and Joe walked over to their friends.
âAny news of Chet and Biff?â Tony asked.
âNothing but a postcard,â Frank answered.
âWhat do you think really happened to them?â Jerry asked worriedly. âDid they go off on a mission of their own? Or were they kidnaped?â
âWe donât know,â Frank confessed. âBut there havenât been any ransom notes.â
âItâs dull around here without the fellows.â Tony sighed. âWe were going on a nice camping trip.â
âChet and Biff told us about it,â said Joe. âFrank and I have an idea maybe theyâre being hidden on one of the coast islands.â
âCould be,â Tony said. âI remember Biff mentioned Hermit Islandâthe one owned by a queer old recluse who lives on it.â
âHe mentioned that to us, too,â Joe recalled. âI wonder if that old man has seen any sign of Chet and Biff?â
âSay!â Tonyâs face suddenly lighted up. âWhy donât we get your boat and go out for a look at Hermit Island? Itâs early enough yet. How about it?â
âGood idea!â Jerry exclaimed.
âRight!â Frank said enthusiastically.
Joe was already on his feet. âCome on! Letâs go!â To Frank he said, âThe mystery of Mr. Frenchâs mix-up last night can wait.â
Jerry and Tony paid for their ice cream, and the four hurried out to Jerryâs car. A short drive brought them to the Hardy boathouse.
âLetâs take both our boats,â Tony proposed. âWe might need themâif we find Chet and Biff.â
They piled into the Sleuth and Frank steered the craft down to the dock where Tony kept the Napoli. Just as the two boats were ready to cast off, Callie Shaw and Iola Morton walked out onto Tonyâs dock.
âOh, are you boys going for a ride?â Callie asked. âMay we come along?â
âGosh, Callie,â Frank said doubtfully, âthis isnât exactly a pleasure cruise. Weâre bound for Hermit Island to look for Chet and Biff.â
âOh, then you have to take us,â pleaded Iola. âAfter all, Chetâs my brother.â Her eyes filled with tears. âPlease, Frank.â
âIolaâs right,â Joe agreed. âThe girls want to find Chet and Biff as much as we