This is a very short story that's part of a larger collection of short stories by different authors. It had been quite some time since I last read some Percy Jackson, but I was very glad I did return to the world of the Modern Greek Gods.
The writing and Percy's wit will be exactly what you'd expect after reading the series. My only complaint is the length. It really is too short, Grover birthday is glossed over in this way. It did remind me I should pick up the next series by Rick Riordan!