  Context. The Galactic centre is hazardous for stellar clusters because of the
strong tidal force. Supposedly, many clusters were destroyed and contributed
stars to the crowded stellar field of the bulge and the nuclear stellar
cluster. However, it is hard to develop a realistic model to predict the
long-term evolution of the complex inner Galaxy, and observing surviving
clusters in the central region would provide crucial insights into destruction
processes. Aims. Among hitherto-known Galactic globular clusters, VVV CL002 is
the closest to the centre, 0.4 kpc, but has a very high transverse velocity,
400 km s$^{-1}$. The nature of this cluster and its impact on Galactic
astronomy need to be addressed with spectroscopic follow-up. Methods. Here we
report the first measurements of its radial velocity and chemical abundance
based on near-infrared high-resolution spectroscopy. Results. We found that
this cluster has a counterrotating orbit constrained within 1.0\,kpc of the
centre, as close as 0.2 kpc at the perigalacticon, confirming that the cluster
is not a passerby from the halo but a genuine survivor enduring the harsh
conditions of the Galactic mill's tidal forces. In addition, its metallicity
and $\alpha$ abundance ([$\alpha$/Fe] $\simeq +0.4$ and [Fe/H]$=-0.54$) are
similar to some globular clusters in the bulge. Recent studies suggest that
stars with such $\alpha$-enhanced stars were more common at 3 - 6 kpc from the
centre around 10 Gyrs ago. Conclusions. We infer that VVV CL002 was formed
outside but is currently falling down to the centre, exhibiting a real-time
event that must have occurred to many clusters a long time ago.
