Un día, delante de su puerta, Tilda, la ratoncita blanca, encuentra un huésped totalmente inesperado: ¡un huevo! Tilda decide al instante ocuparse de él, pues ya sabe que a un huevo hay que darle calor, cuidarlo y protegerlo. Lo que ignora, sin embargo, es que bajo la cáscara se esconde una gran sorpresa. --From publisher's description.

One day, Tilda, the white mouse, finds an egg outside her door, and she decides to keep it and look after it. She knows that eggs have to be kept warm and have to be protected. What she doesn't know is what is inside this egg.