Book description: Teo and Titti are twins, they are ten and a bit, and they are living with their grandmother while they wait for their parents to return from a photographic safari. However, in the attic also lives Tano the Monaciello, who immediately becomes Teo's friend.
But how will the boy keep this secret friendship hidden?
Titti can read his mind! It's a big mess, and as if that weren't enough, Nerea shows up at the door asking for help to be transformed back into a mermaid.
Mission impossible?
We'll find out.