Helpmate in 5
In helpmates:
- Black moves first
- The sides cooperate to help White mate Black
So in this case there will be 5 Black moves and 5 White moves (alternating between Black and White as usual), and the last White move will deliver mate.
Helpmates often have very artificial looking arrangements of the pieces which does not appeal to me. However, this one is relatively normal and I found it entertaining to solve.
Remember, Black is trying to get mated! Good luck!