  We consider a transport setup containing a double-dot connected by a
continuum. Via an exact solution of the time-dependent Schr\"odinger equation,
we demonstrate a highly non-Markovian quantum-coherence-mediated transport
through this dot-continuum-dot (DCD) system, which is in contrast with the
common premise since in typical case a quantum particle does not reenter the
system of interest once it irreversibly decayed into a continuum (such as the
spontaneous emission of a photon). We also find that this DCD system supports
an unusual steady state with unequal source and drain currents, owing to
electrons irreversibly entering the continuum and floating there.
