  We study the quantum motion of null shells in the quantum space-time of a
black hole in loop quantum gravity. We treat the shells as test fields and use
an effective dynamics for the propagation equations. The shells propagate
through the region where the singularity was present in the classical black
hole space-time, but is absent in the quantum space-time, eventually emerging
through a white hole to a new asymptotic region of the quantum space-time. The
profiles of the shells get distorted due to the quantum fluctuations in the
Planckian region that replaces the singularity. The evolution of the shells is
unitary throughout the whole process.
