Celebrating 30 years, a retiring detective’s last case is to investigate a theft where he must protect the criminals he planned the crime with.

I guess here the detective is also involved in this case of theft, but i think he should rather protect his own reputation from being destroyed instead of protecting the criminals, though i realize in the process of protecting the criminals, he is indirectly protecting himself but i guess it will be more fascinating if his major problem or goal here is to protect himself or his 30 year reputation. Meanwhile i think it's going to be a story to watch out for. Hope this helps.

This is a little confusing, Was the Detective in on the crime?