I was tidiing some things when I came across a children's book I received "In memory of CE1 - may 2000" (CE1 = Year 3 or 2nd grade). It is entitled "Où cours-tu la tortue ?", and simply summarised:
"At a turtle's pace, Adele, obstinate,
looks for home and friends...
Will she find?"
I offer you to follow this story ;)

French grid : "Où cours-tu la tortue ? (0)"

Difficulty : ***

Tested, logical.
Not require any specific method, only single-line logic.
Good "blackenage".