Ncis new orleans season 2 episode 21

A great choice!

NCIS: New Orleans Season 2 Episode 21 is titled "How Much Pain Can You Endure". Here's a brief summary:

The team investigates the murder of a former Navy SEAL who was working as a private security contractor. The victim was found with a mysterious tattoo on his chest, which leads the team to suspect that he was involved in some shady dealings. Meanwhile, Sebastian's past comes back to haunt him when his former partner, who he thought was dead, shows up alive and asks for his help.

This episode originally aired on April 19, 2016.