  Since the discovery of superconductivity and correlated insulator at
fractional electron fillings in the twisted bilayer graphene, most theoretical
efforts have been focused on describing this system in terms of an effective
extended Hubbard model. However, it was recognized that an exact tight binding
model on the Moir\'{e} superlattice which captures all the subtleties of the
bands can be exceedingly complicated. Here we pursue an alternative coupled
wire description of the system based on the observation that the lattice
relaxation effect is strong at small twist angle, which substantially enlarges
the AB and BA stacking domains. Under an out-of-plane electric field which can
have multiple origins, the low energy physics of the system is dominated by
interconnected wires with (approximately) gapless $1d$ conducting quantum
valley hall domain wall states. We demonstrate that the Coulomb interaction
likely renders the wires a $U(2)_2$ $(1+1)d$ conformal field theory with a
tunable Luttinger parameter for the charge $U(1)$ sector. Spin triplet and
singlet Cooper pair operator both have quasi-long range order in this CFT. The
junction between the wires at the AA stacking islands can lead to either a two
dimensional superconductor, or an insulator.
