A line $L$ on the plane $2x + y - 3z + 5 = 0$ is at a distance $3$ unit from the point $P(1, 2, 3)$. A spider starts from point $A$ and after moving $4$ units along the line $\frac{x-1}{2}=\frac{y-2}{1}=\frac{z-3}{-3}$ it reaches to point $P$. and from $P$ it jumps to line $L$ along the shortest distance and then moves $12$ units along the line $L$ to reach at point $B$. Find the distance between points $A$ and $B$.
Could someone give me hint to solve this problem, I am not able to proceed. As $P$ lies on plane, hence their will be infinite lines on plane which will be at distance of $3$ units from point $P$ so how to proceed?