§ 136.505 Effect of allowance of motion

When a judge grants a motion in arrest of judgment, it basically wipes out the conviction and puts the defendant back to where things stood before they were ever charged. It's like the indictment never happened.

This doesn't mean the defendant is off the hook for good. The state can usually still bring new charges against the defendant for the same alleged crime, since the case is just starting over from that earlier point. What it does mean is that the conviction and any sentence that came with it are no longer in effect, and the case goes back to square one.