Quest of the Golden Ape by Stephen Marlowe

At first Retoc the Abarian was too stunned by what he witnessed to think coherently. With the other Tarthians of royal blood he had received an unexpected summons to appear at the Royal Dock on the River of Ice and, before he could even try to fathom what it was about, an escort of Nadian guards had come to fetch him.

It was cold and murky on the banks of the River of Ice. The two men, Retoc and Hultax had arrived barely in time to see them unfastening the hawsers of the Royal Barge. Curious, he pushed closer through the crowd of nobles. Suddenly, before the barge was quite unmoored, as it swayed and rocked on the currents of the river, Nadian soldiers appeared with a platform on poles slung across their shoulders, the usual means of intra-city transportation for Nadian royalty. But this was no royalty Retoc saw on the platform, although they were dressed as royalty.