This time of the year, teams are sometimes willing to do anything to get the piece that might get them closer to their goal of winning a Stanley Cup. Sometimes that includes dealing a top prospect. If a team is sure they're getting something back that is a sure thing, they are more often than not willing to part with a top prospect.
However, each team has a prospect that they should not even consider trading. Teams might ask for them, but if they do, it would be wise for the team that received the phone call to hang up.
Here is the most untouchable prospect for each NHL team.