When Múinteoir Emer has to have a bunion removed, Milly's class gets a substitute teacher while she's off.

But Mr Wright is not like any teacher Milly has ever had before. He's super strict and obsessed with PE. So much so, he convinces their principal, Mr Manley, to allow their class to organise a Lá Spóirt for the whole school.

Milly's soon signed up for the egg-and-spoon race, the three-legged race and even a bit of archery … Sure, what could possibly go wrong?