  We found black hole evolution on a quantum-gravitational scattering framework
with an aim to tackle the black hole information paradox. With this setup,
various pieces of the system information are explicit from the start and
unitary evolution is manifest throughout. The scattering amplitudes factorize
into the perturbative part and nonperturbative part. The nonperturbative part
is dominated by an instanton-type contribution, i.e., a black hole analogue of
the Coleman-De Luccia's bounce solution, and we propose that the Hawking
radiation be identified with the particles generated by the vacuum decay. Our
results indicate that the black hole degrees of freedom are entangled not only
with the Hawking modes but also with the pre-Hawking modes. The Wald's entropy
charge measures their entanglement. The full quantum-gravitational entropy is
defined as the vev of the Wald entropy charge. With this definition a {\em
shifted} Page-like curve is generically generated and its quantum extension is
readily defined.
