  We consider a covariant causal set approach to discrete quantum gravity. We
first review the microscopic picture of this approach. In this picture a
universe grows one element at a time and its geometry is determined by a
sequence of integers called the shell sequence. We next present the macroscopic
picture which is described by a sequential growth process. We introduce a model
in which the dynamics is governed by a quantum transition amplitude. The
amplitude satisfies a stochastic and unitary condition and the resulting
dynamics becomes isometric. We show that the dynamics preserves stochastic
states. By "doubling down" on the dynamics we obtain a unitary group
representation and a natural energy operator. These unitary operators are
employed to define canonical position and momentum operators.
