In a more light - hearted scenario, Emily could be a mischievous pet, like a cat or a dog that has run away, and the 'catching Emily' part is all about the family trying to bring their beloved pet back home.
Well, without having read 'perfect timing a harrigan family novel', it's difficult to give a detailed account. However, based on the title, it seems that the story will center on the Harrigan family. The 'perfect timing' part might imply that there are events in the family's story that occur at opportune or fateful times. It could be about how these moments shape the family's dynamics, their relationships with one another, and their individual and collective destinies.