In the first two somewhat uneven mysteries in the fourth season, the team seemed fractured (spoiler alert!) after the arrest of Dr. Zack Addy (Eric Millegan) for conspiring with a serial killer and the split of Angela Montenegro (Michaela Conlin) and fiance Dr. Jack Hodgins (T.J. Thyne). There was also conflict after Dr. Camille Saroyan (Tamara Taylor) had an affair with Angela's ex-husband. In the third story this season, "The Finger in the Nest," the team finally addressed their problems with the help of psychiatrist Dr. Lance Sweets (John Francis Daley). While the forensic team members and Agent Booth were at first dissatisfied with Dr. Sweets' introduction, he helped Dr. Hodgins (who seems to be turning into Dr. House!) come to terms with the disruption in the team. Sweets also learned what was bothering Booth's son after he found a finger in a birds' nest.
Dr. Brennan was also affected by the case's connection to a dogfighting operation operating outside the law. This episode has an important message about treating animals humanely. Bones is the only television show mentioned in both my anthropology classes at college, as an example of how anthropology is portrayed relevantly to society today. As a forensic anthropologist, Dr. Brennan (and the character's creator, Kathy Reichs), applies her knowledge of human cultures and bone structure to solving crimes. Emily Deschanel and David Boreanaz have great chemistry together as they solve mysteries using Brennan's analytical approach and Booth's understanding of human behavior. It's a lot of fun to watch and also incorporates the science in an entertaining way.