way back.
The girls were let off at their homes with quick good-nights, then Frank and Joe continued on to Elm Street. The first floor of their home was well lighted.
Joe put the car away and the boys entered through the back door. They were faced immediately by their mother and Aunt Gertrude, who had waited up for them.
âWherever in the world have you been?â Mrs. Hardy inquired with a worried look.
âA body canât get any sleep any more!â Aunt Gertrude complained. âDo you know what time it is?â
âOf course we do,â Joe said, stifling a yawn with the back of his hand. âWe were mixed up in a new development in our case. We just couldnât help being late.â
âLooks as if you were mixed up in a mud bath,â Mrs. Hardy said, the comers of her mouth relaxing.
âYouâre not kidding!â Frank kicked off his dirty shoes and set them beside the kitchen door. Joe followed suit.
âAunt Gertrude, weâre lucky to be back at all,â Joe said. âWe got chased, shot at, andââ
Aunt Gertrude wrung her hands, and an agonizing look crossed her face. âYouâre involved with gangsters again!â she wailed and turned to Mrs. Hardy. âLaura, itâs too dangerous for these boys to play detective!â
âIt wasnât any play, I can tell you that!â Frank observed as he stripped off his mud-spattered sport shirt.
âHere, give me those dirty things,â Mrs. Hardy said. âI donât want you to trail mud into your room.â
âThanks, Mother.â Joe grinned.
Gertrude Hardy clucked disapprovingly. âWell,â she said, âat least we can all go to bed now. Frank, Joe, mind youâre up in time for breakfast and church!â
The next day was Sunday. Early afternoon Sam Radley dropped in and discussed the latest turn of events. After the Hardys had told him everything that had transpired the day before, Frank concluded, âThat assistant at the airport, Bill Zinn, is a prime suspect.â
âSo are Mudd and Nettleton,â Radley added. âThey should be investigated.â
âThatâs where you could help us,â Joe put in. âCould you start checking on Zinn? You know what I meanâhis background and all that?â
âBe glad to.â
âGreat,â Frank said. âMeanwhile, weâll go back to Muddâs place and do some further sleuthing there.â
After Radley had left, Joe said, âWhat do you have in mind about the airplane junkyard, Frank?â
âWe need to follow up that tailpost clue. Remember Chetâs fuselage? The tailpost was missing.â
âNow I get it,â said Joe, snapping his fingers. âLast night Nettleton was working on the tailpost of that plane. Maybe something was hidden there!â
Frank nodded and Joe went on, âWhatâs your strategy?â
âI really donât have any yet,â Frank replied. âWe could ask ChetâWow! That gives me an idea. Come on!â Frank went to the telephone and dialed the Morton farm.
Chet answered. âHello, Frank. Youâre lucky to find me in. I was just practicing loops.â
âOh, good,â Frank said. âAre you ready for an Immelmann yet?â
âHa, you canât stump me,â Chet said. âIsnât that the outside loop invented by that German ace?â
âLetâs get back down to earth,â Frank said. âThereâs something Iâd like you to do for us.â
âListen,â Chet said, âmy pilotâs training canât be interrupted byââ
âCome on,â Frank urged. âAll we want you to do is ask Mudd for a tailpost.â
Silence for a moment, as Chet mused. âCome to think of it, I could use one, too. And maybe some other parts. Okay, itâs a deal. When do we go back to Beemerville?â
âTomorrow. And listen, Chet. We want you