  A purely electronic mechanism is proposed for the unconventional
superconductivity recently observed in twisted bilayer graphene (tBG) close to
the magic angle. Using the Migdal-Eliashberg framework on a one parameter
effective lattice model for tBG we show that a superconducting state can be
achieved by means of collective electronic modes in tBG. We posit robust
features of the theory, including an asymmetrical superconducting dome and the
magnitude of the critical temperature that are in agreement with experiments.
