We perform high resolution AREPO simulations of an M51-like galaxy aimed at the study of the dense molecular phase of the ISM in the larger galactic-scale context. By including important physics like star formation, stellar feedback, a non-equilibrium chemical network and self-shielding from UV radiation, we are able to follow in great detail the formation and destruction of GMCs. In this first study we address the impact of the interaction on the star formation activity of the system. In particular we focus on the following central question: is the interaction the main driver of star formation in an M51-like galaxy?