The motion of a massive particle with intrinsic spin in a gravitational Einstein vacuum plane wave background is explored using the
pole-dipole approximation to the Dixon multipole expansion for matter with compact support. Motivated by application to astrophysical
processes the dynamical behaviour of the spin and particle motion
is described by numerically solving a system of non-linear ﬁrst order
ordinary diﬀerential equations. Some results are displayed in a reference frame adapted to the transverse nature of a monochromatic
polarised gravitational wave of arbitrary intensity.