  Two ordering states, antiferromagnetism and nematicity, have been observed in
most iron-based superconductors (SCs). In contrast to those SCs, the newly
discovered SC CaK(Fe$_{1-x}$Ni$_x$)$_4$As$_4$ exhibits an antiferromagnetic
(AFM) state, called hedgehog spin-vortex crystal structure, without nematic
order, providing the opportunity for the investigation into the relationship
between spin fluctuations and SC without any effects of nematic fluctuations.
Our $^{75}$As nuclear magnetic resonance studies on
CaK(Fe$_{1-x}$Ni$_x$)$_4$As$_4$ (0$\le x\le$ 0.049) revealed that
CaKFe$_4$As$_4$ is located close to a hidden hedgehog SVC AFM quantum-critical
point (QCP). The magnetic QCP without nematicity in
CaK(Fe$_{1-x}$Ni$_x$)$_4$As$_4$ highlights the close connection of spin
fluctuations and superconductivity in iron-based SCs. The advantage of
stoichiometric composition also makes CaKFe$_4$As$_4$ an ideal platform for
further detailed investigation of the relationship between magnetic QCP and
superconductivity in iron-based SCs without disorder effects.
