During certain rains, water would drip from the fireplace. Where the roof meets the chimney was the first place to look.
What did the hole say to the water? "Come on in!"
Fortunately, the damage was minimal.
Building a small cricket diverted the water away from the inside corner created by the roof and chimney.
Add new step and counter flashing at the chimney, seal the siding J-channel against the brick, and it's water tight.