We consider the totally asymmetric simple exclusion process (TASEP) with non-random initial condition having density $ρ$ on $\mathbb{Z}_-$ and $λ$ on $\mathbb{Z}_+$, and a second class particle initially at the origin. For $ρ<λ$, there is a shock and the second class particle moves with speed $1-λ-ρ$. For large time $t$, we show that the position of the second class particle fluctuates on a $t^{1/3}$ scale and determine its limiting law. We also obtain the limiting distribution of the number of steps made by the second class particle until time $t$.