  We develop EventMover, a differentiable parton shower event generator. This
tool generates high- and variable-length scattering events that can be moved
with simulation derivatives to change the value of the scale
$\Lambda_\mathrm{QCD}$ defining the strong coupling constant, without
introducing statistical variations between samples. To demonstrate the
potential for EventMover, we compare the output of the simulation with $e^+e^-$
data to show how one could fit $\Lambda_\mathrm{QCD}$ with only a single event
sample. This is a critical step towards a fully differentiable event generator
for particle and nuclear physics.
