Current flowing from lower to higher potential

In the above circuit, two cells are connected in series to an external resistance $R$ . Now the current going from point $A$ must return back to point $B$ of the cell. But for that it has to pass through $DC$ path. We all know current flows from higher potential to lower potential. But here potential of $D$ is less than the potential of $C$ since $C$ is the positive end and $D$ is the negative end of the battery. How is this possible?