Robmore came strolling back and joined them.
"All right!" he murmured. "Four pairs of eyes, beside ours—that's three pairs more—on him! My men are close up to him, too. See 'em? One, two, three, four! All round him, though he doesn't know. I shan't let him go, whether Matherfield turns up or not. Cool customer, eh?"
"The train's due," said Hetherwick. He had Rhona's hand within his arm, and he felt it tremble. "Yes," he whispered, bending down to her, "that's how I feel. Tense moment, this. But that scoundrel there——"
Baseverie was glancing at the big clock. He turned from it to the platform behind the gates, looking expectantly along its lighted surface. The others looked, too. A minute passed. Then, out of the gloom at the further extremity of the vast station, an engine appeared, slowly dragging its burden of carriages and came sighing like a weary giant up the side of the platform. The passengers in the front compartments leapt out and began filing towards the exit.
"Now for it," muttered Robmore. "Keep back, you two! My men'll watch him—and whoever's here to meet him, for he's expecting somebody."
Nothing happened for the first minute. The crowd of discharged passengers, men and women, civilians, soldiers, sailors, filed out and went their ways. Gradually it thinned. Then Hetherwick's arm was suddenly gripped by Rhona for the second time, and he saw that she was staring at something beyond the barrier.
"There!" she exclaimed. "There—the man in the grey coat and fawn hat! That's the man who drove the car! See! Baseverie sees him!"
Hetherwick looked and saw Baseverie lift a hand in recognition of a young, fresh-faced man, who was nearing the ticket-collectors, and who carried in his right hand a small, square parcel. But he saw more. Close behind this young man came Matherfield on one hand and Quigman on the other. They drew closer as he neared the gate, and on its other side the detectives drew closer to Baseverie.
"Now then," whispered Robmore, and stole swiftly forward.
It was all over so swiftly that neither Hetherwick nor Rhona knew exactly how the thing was done. Before they had realised that the men were trapped, or the gaping bystanders had realised that something was happening under their very noses, Baseverie and his man were two safely handcuffed prisoners in the midst of a little group of silent men who were hurrying both away. Within a moment captors and captives were lost in the outer reaches of the station. Then the two watchers suddenly realised that Matherfield, holding the square parcel in his hand, was standing close by, a grim but highly satisfied smile in his eyes. He held the parcel up before them.