CONTENTS

CHAPTER
I [A MYSTERIOUS DISAPPEARANCE]
II [A NIGHT RIDE]
III [THE WARNING]
IV [A STRANGE REAPPEARANCE]
V [ANOTHER WARNING]
VI [TROUBLE AT SQUARE M]
VII [DOUBLING UP]
VIII [DRY AGAIN]
IX [A SHOT IN THE NIGHT]
X [INTO THE TUNNEL]
XI [THE RUSH OF WATERS]
XII [THE RISING FLOOD]
XIII [WHERE DID IT GO?]
XIV [A NIGHT ATTACK]
XV [THE BRANDING IRON]
XVI [QUEER ACTIONS]
XVII ["GERMS!"]
XVIII [ROPED!]
XIX [AN EXPEDITION IN THE DARK]
XX [INTO THE DEPTHS]
XXI [THE FIGURE ON THE ROCK]
XXII [THE WATER GATE]
XXIII [THE CONSPIRATORS]
XXIV [A POWERFUL STREAM]
XXV [HAPPY VALLEY]