One possible fanfiction plot could be that Adam Ruzek is on a routine patrol when suddenly he's caught in a crossfire. His partner races to his side as he lies bleeding. The team then has to scramble to find the shooter while also trying to keep Adam alive. They call in all their favors and resources, and in the end, Adam pulls through after a tense and harrowing surgery.
Family loyalty is a common theme. The sister might be shown as being very loyal to Ruzek, standing by him through thick and thin in his police work. Another theme could be protection. Ruzek might be protective of his sister, or vice versa, in the face of the dangerous world they live in because of his job.
I'm not sure of specific 'Chicago PD Ruzek sister fanfic' off the top of my head. But you could also try looking on fanfic forums. Sometimes fans discuss their favorite stories there, and you might be able to get some leads on good ones related to Ruzek's sister.
Emotionally, it would be a rollercoaster. Adam's friends would be distraught. Jay Halstead, for example, would be furious and would stop at nothing to find the person who shot Adam. The female characters might be more openly emotional, crying and praying for Adam's recovery. And the rookies in the department would look at the situation with a mix of fear and admiration for how the more experienced officers are handling the crisis.
A crossover could involve a character from Chicago Fire having a personal connection to a case the Chicago PD is working on. Maybe a firefighter's family member is wrongly accused of a crime. The firefighter then teams up with the PD detectives to clear their family member's name. This would bring in elements of loyalty, family, and the different skills of both groups. They could share information and resources to solve the mystery.
One great 'chicago pd fanfic' is 'The Blue Line Bonds'. It delves deep into the relationships between the characters outside of their regular work scenarios. The character development is on point and it gives a fresh perspective on the show's dynamics.
Well, it is. 'Chicago PD' takes elements from real - world happenings within the Chicago Police Department. They might fictionalize some aspects for the sake of drama, but at its core, it's rooted in the true nature of police work in Chicago. For example, the types of crimes they deal with and the general environment are reflective of the real city.
A fanfic could focus on Voight's backstory. Maybe he has an old case that resurfaces, and he has to deal with the ghosts of his past while still leading his team. It could show his vulnerability and determination in the face of personal and professional difficulties.