720 "Wolfe in Sheep's Clothing"
The Russians have kidnapped Billy Gantry, last seen in ep 713, and are forcing Ryan, who has taken over Billy's dad's debt to work for them b/c he doesn't have enough money to pay off the debt all the way. They also figure if they have a cop in their pocket they can own the city.
At the end of 719 Ryan is kidnapped and beat up til he agrees to do things their way....as an added incentive, Ryan later finds out, they have snatched Billy to make sure he cooperates.
Andrei, holds Billy hostage while he gives Ryan instructions on how to clear one his man in the murder of Ian Winter...a moneys exchange businessman who is murdered in his office. Andrei communicates with Ryan over the phone telling to "clean" things up or Billy dies. He fires shots while on the phone to scare Ryan and drive his point home.
Ryan purposely hides a shell casing he finds at the scene in his pocket, he mishandles evidence by picking it up w/o gloves in front of Calleigh and Eric who confront him but he remains silent and yes, he even frames the security guard at the building for Ian's murder...all to save Billy.
While Ryan is fudging evidence and the rest of the team is honestly working the case, Horatio finds out through Billy's dad that he didn't show up to school and heads off on his own in search of the boy.
The ep sounds like it is going to an extremely intense one.