When Jack apparently goes rogue, Oversight approaches Mac at his new home in Nigeria and asks him to come back to bring in his friend.
One of Jack's old Delta buddies comes to him saying that another old buddy needs help. Meanwhile, Matty sends Wilt, Riley, and Leanna on a mission of their own while Jack and Mac are out of the country.
While his teammates infiltrate a tech college to learn who is recruiting students to plant terrorist bombs, Jack works with Billy to track down a skip... and learn more about Riley's lover.
With Jack reporting to the Secretary of Defense and Wilt in LA, Mac and Riley are the closest agents to Georgia when a children's hospital runs out of air and rebel activity prevents anyone from delivering a vital tanker of liquid oxygen. Riley helps MacGyver decide whether or not to allow his father back into his life.
When an operation that can lead Phoenix to Walsh goes bad, Oversight calls in Mac and Jack to rescue him. Meanwhile, Wilt and Riley go undercover as newlyweds to get the goods on a Chinese spy.
Murdoc abducts Nasha as leverage to force Mac to help him recover his kidnapped son Cassian. As the two men work together, Mac gets an up-close view on the sociopathic killer... and his equally amoral wife.
After a senator contacts her about his being blackmailed, Matty sends the team on an off-the-books mission to Ghana to recover the senator's hard drive... which also has a secret file named Dragonfly on it.
While Jack is in Brazil, Mac, Wilt, and Riley team up with Mac's old partner Charlie to go after the Ghost when a British agent brings them intel on the bomb maker's location.
A vial with a deadly virus goes missing from the CDC, and Mac, Wilt, and Jack are called in to investigate. Meanwhile, Billy takes Riley on a cross-country drive and promises a surprise at the end, but their car is stolen.
When Matty's former husband Ethan's undercover assignment is blown and the CIA disavows him, Matty asks the team to help her rescue Ethan before the criminals he's with realize who he really is and kill him.
A mysterious captor takes Jack and Mac captive while they're on their way to Las Vegas for their yearly Maniversary. Meanwhile, Matty sends Wilt, Riley, and Leanna on a mission to copy data inscribed on a diamond belonging to the niece of a terrorist.
When a team of thieves is captured by the government, Matty calls upon the leader--a soccer mom by day, a thief by night--to help them steal a dirty bomb that someone in Russia is selling from within a highly-guarded tech company.
Mac takes Wilt and Riley on a wilderness survival trek and they run into robbers. Meanwhile, Jack accompanies Matty as she takes Ethan and his family to a secure location, and someone sends Jack a photo of a man from his past.
An international crime lord offers to turn himself in and give evidence against his former organization in if Matty will make sure that he gets to attend his daughter's wedding. Matty agrees, but soon finds out that there are other people that want the crime lord dead. Meanwhile, Jack tells Mac that the mission will be his last one for Phoenix.
The team deal with Jack's replacement while helping an ATF agent find her missing dog Cody... which is the key to breaking up a gun-smuggling operation.
Mac persuades Matty to let him bring back the body of a test pilot who was flying over a foreign country with a lidar that Mac designed... and may have caused the jet to crash. Elwood prepares for his first day on the job, and Desi stumps Sparky with a riddle.
Mac, Desi, and Riley go to Greenland to investigate the disappearance of a guard at a top-secret international seed vault. Wilt follows Oversight at Mac's request to find out what their boss is doing in secret.
Phoenix discovers that Murdoc's mentor, Nicholas Helman, is killing the team responsible for flipping a syndicate member to testify against his employers. They consult with Murdoc on how to stop Nicholas, only to discover that Murdoc and Nicholas have plans of their own.
While Mac and Desi help migrants in Bosnia, Wilt finds himself in a booby-trapped SUV with no way out.
When two American backpackers disappear during a No-Go Challenge scavenger hunt in South America, the parents' tearful pleas reach James. He orders the Phoenix team undercover as backpackers to find the missing kids and bring them home alive.
Ethan asks Matty to help him recover his abducted wife and daughter... by betraying the CIA. Riley accompanies Billy and Mama to Paris to bring in a terrorist financier and bail jumper, and learns something shocking about Billy.
The man responsible for the team doxxing and the rigged SUV reveals himself and his motive for targeting Phoenix. This cunning new adversary's carefully crafted plans force Mac to make an impossible choice: save the life of a friend or save the lives of hundreds of innocents. Mac receives new information that will drive a wedge between him and his father.
