Hudson House, the social settlement presided over by Miss Fanny and affected for business reasons by Mock Hen, was a mile and a half away.  But Mock took his time.  Twenty-five full minutes elapsed before he leisurely climbed the steps and slipped into the big reading room.  There was no one there and Mock deftly turned back the hand of the automatic clock over the platform to three-fifty-five.  Then he began to whistle.  Presently Miss Fanny entered from the rear room, her face lighting with pleasure at the sight of her pet convert.

“Good afternoon, Mock Hen!  You are early to-day.”

Mock took her hand and stroked it affectionately.

“I go Fulton Mark’ buy li’l’ terrapin.  Stop in on way to see dear Miss Fan’.”

They stood thus for a moment, and while they did so the clock struck four.

“I go now!” said Mock suddenly.  “Four o’clock already.”

“It’s early,” answered Miss Fanny.  “Won’t you stay a little while?”

“I go now,” he repeated with resolution.  “Good-by li’l’ teacher!”

She watched until his lithe figure passed through the door, and presently returned to the back room.  Mock waited outside until she had disappeared.

Then he changed back the clock.

* * * * *

“We’ve got you, you blarsted heathen!” cried Mooney hoarsely as he and two others from the Central Office threw themselves upon Mock Hen on the landing outside the door of his flat.  “Look out, Murtha.  Pipe that thing under his arm!”

“It’s a bloody turtle!” gasped Murtha, shuddering

“What’s the matter, boys?” inquired Mock.  “Leggo my arm, can’t yer?  What’d yer want, anyway?”

“We want you, you yellow skunk!” retorted Mooney.  “Open that door!  Lively now!”

“Sure!” answered Mock amiably.  “Come on in!  What’s bitin’ yer?”

He unlocked the door and threw it open.

“Take a chair,” he invited them.  “Have a cigar?  You there, Emma?”

Emma Pratt, clad in a wrapper and lying on the big double brass bedstead in the rear room, raised herself on one elbow.

“Yep!” she called through the passage.  “Got the bird?”

Mock looked at Murtha, who was carrying the terrapin.

“Sure!” he called back.  “Sit down, boys.  What’d yer want?  Can’t yer tell a feller?”

“We want you for croaking Quong Lee!” snapped Mooney.  “Where have you been?”

“Fulton Market—­and Hudson House.  I left here quarter of four.  I haven’t seen Quong Lee.  Where was he killed?”

Mooney laughed sardonically.

“That’ll do for you, Mock!  Your alibi ain’t worth a damn this time.  I saw you myself.”

“You saw someone else,” Mock assured him politely.  “I haven’t been in Chinatown.”

“Say, what yer doin’ wit’ my Chink?” demanded Emma, appearing in the doorway.  “He was sittin’ here wit’ me all the afternoon, until about just before four I sent him over to Fulton Market to buy a bird.  Who’s been croaked, eh?”