in secret meeting

The man had to buy them in secret, meeting his connection precisely at 10:30 p.m. at an arranged location.

A rumor got out that old Portiphar had betrayed Valentine into the hands of the law, and that a number of negroes in secret meeting had sworn the death of the traitor whenever and wherever either one of them could take him.

It was so in New Orleans, where the leading commercial forces of the city, in secret meeting, called the health officer before them and brow-beat him into concealing the presence of yellow fever, lest other cities quarantine against their commerce.