“I guess Dad will think we aren’t such poor detectives after all,” Joe exulted, as they brought their motorcycles to a stop in the yard of the Hardy home.

Their father was in the library, but in their excitement the lads forgot to rap at the door and rushed into the room without ceremony.

“Dad, we’ve found a clue!” cried Joe, when he saw his father sitting at the huge oak desk. Then he fell back, embarrassed, when he saw that there was someone else in the room.

“Beg pardon!” said Frank, and the boys would have retreated, but Mr. Hardy’s visitor turned around and they saw that it was Perry Robinson.

“It’s only me,” said Slim. “Don’t go.”