Last week's "NCIS: New Orleans" epsisode, "The Insider," tested the courage and strength of Dr. Loretta Wade and the NCIS team.

The episode began with a naval officer named Felix Armstrong who dropped dead as he attempted to pass through airport security. Dr. Loretta Wade arrived at the airport with the NCIS team to investigate. She, Sebastian and Danny took Felix to the coroner's office for an autopsy. A man entered the office saying that he needed Felix's body and had a letter from the family granting permission. Dr. Wade said the autopsy must be performed before the body can be released. The man pulled a gun on her. He ordered everyone to put their phones on the table and bag up Felix's body.

While other NCIS members investigated without knowledge of Loretta, Sebastian and Danny being held hostage, the gunman ordered Sebastian to cut open Felix and get a flash drive out of his stomach, which Sebastian did.

Danny tried to tackle the gunman and was shot in the chest. His lungs filled with blood. Sebastian had to cut open Danny's chest and drain the blood so that he didn't die.

LaSalle and Merr discovered the gunman's name was Marcus. Marcus's brother Nathan had died while serving in the Navy under suspicious circumstances. Marcus had emailed the Navy threatening to expose their shady investigation if they didn't tell him what happened to Nathan.

Felix's commanding officer Capt. Dawson arrived at the morgue with FBI agents. He revealed that two days earlier Felix downloaded national security information on to a hard drive and swallowed it. The NCIS team realized that Felix meant to give the flash drive to Marcus.

Marcus allowed Sebastian and Danny to leave the morgue in an ambulance. Dwayne gave Marcus the file and explained that his brother Nathan was killed by an Ala Majid terrorist front working with the U.S. Navy to take down a Syrian official, but instead, they killed Nathan. Marcus was devastated.

The FBI stormed the office, arrested Marcus and retrieved the flash drive.

Danny stabilized at the hospital with Loretta seated at his bedside. She broke down and Dwayne comforted her.

On the next "NCIS: New Orleans" episode, "Rock-A-Bye Baby," a Navy commander's car is stolen with his baby inside. The NCIS team investigate to determine whether it was a random carjacking or a targeted abduction. Diane Neal returns to the show as Coast Guard Investigative Service Special Agent Abigail Borin.

Watch "NCIS: New Orleans" Episode 20, which airs on Tuesday, April 14, at 9 p.m. ET on CBS.