We report the measurement of the time-dependent $C\!P$ violating observables in $B_s^0\to D_s^{\mp}K^{\pm}$ decays. The study is performed using a dataset corresponding to 3.0 fb$^{-1}$ of $pp$ collisions recorded in the LHCb detector in Run I of the LHC.
We measure
$C_f = 0.735 \pm 0.142 \pm 0.048$,
$S_f = -0.518 \pm 0.202 \pm 0.073$,
$S_{\bar{f}} = -0.496 \pm 0.197 \pm 0.071$,
$A_{f}^{\Delta \Gamma} = 0.395 \pm 0.277 \pm 0.122$,
$A_{\overline{f}}^{\Delta \Gamma} = 0.314 \pm 0.274 \pm 0.107$,
where the uncertainties are statistical and systematic, respectively. Using these observables, the CKM angle $\gamma$ is determined to be $(127_{-22}^{+17})^\circ$ modulo 180$^\circ$ at 68$\%$ CL, where the uncertainty contains both statistical and systematic components.