The four ugly cats in apartment 3D - Marilyn Sachs

Lily is ten and is faced with a secret problem. She lives in apartment 3B. Two of the neighbours on her floor are friendly and nice, but the other neighbour, Mr Freeman, who lives in apartment 3D, is mean and ugly and disliked by most. So are his four ugly cats who continually yowl and irritate everybody in the building.
When Mr Freeman dies suddenly, all of the neighbours and the landlord want to ship the cats off to the S.P.C.A.
But Lily remembers that Mr Freeman was nice to her once. He invited her in to wait for her mother when she was locked out of her apartment. She remembers his love for the four ugly cats. They were his family; he cared for them and gave them a home. Lily refuses to let the cats be destroyed.
"You have three days," the landlord tells her, "before the apartment will be rented."
But Lily discovers that relocation isn't easy. The cats are ugly and very noisy and nobody wants them. It takes all of Lily's ingenuity and care to accomplish what seems like the impossible: to find homes for the four ugly cats in apartment 3D.