Arson, Babies and Firehouses

Gabby Dawson and Matt Casey are expecting their first child. Gabby has to switch over to arson. There is an arson case from 10 years ago, where there were various fires set throughout the city of Chicago. They have a good idea of who it is, they just haven't gotten proof to make an arrest. This takes place in the time of 7.1, but she doesn't leave at all and there's no aneurysm.