Episodes
Episode: 4x01 | Airdate: Sep 27, 2013
After McGarrett and Wo Fat narrowly escape from maximum security, gunmen storm Five-0 headquarters, compromising Kono and Adam's secret location in Hong Kong and forcing McGarrett to break the law and turn on his own in order to find a kidnapped Catherine.
Episode: 4x02 | Airdate: Oct 4, 2013
Five-0 murder investigation leads the team to help a Texas Ranger who comes to the island to find his missing daughter. Meanwhile, Kono and Adam fight to stay alive when their hidden location is discovered.
Episode: 4x03 | Airdate: Oct 11, 2013
Conspiracy theorist helps Five-0 when a missing artifact is the key to solving a double murder.
Episode: 4x04 | Airdate: Oct 18, 2013
Five-0 investigates the murder of a wedding crasher, and their prime suspect is the runaway bride. Meanwhile, Danny makes a big decision regarding his relationship with Gabby.
Episode: 4x05 | Airdate: Oct 25, 2013
As Catherine's seemingly harmless surveillance job takes a deadly turn, Adam considers making the ultimate sacrifice to save Kono.
Episode: 4x06 | Airdate: Nov 1, 2013
When Halloween comes to Hawaii and a zombie-like man is shot, Five-0 races to stop a madman who is conducting experiments on humans.
Episode: 4x07 | Airdate: Nov 8, 2013
While working the murder case of an undercover ATF agent, McGarrett and the Five-0 team are tasked with watching Mary's newly adopted baby after she gets sick.
Episode: 4x08 | Airdate: Nov 15, 2013
McGarrett and Grover must work together to protect national security after they are tasked by the Governor to serve a warrant to a young computer hacker.
Episode: 4x09 | Airdate: Nov 22, 2013
As Thanksgiving approaches, Five -0 investigates the murder of a secret service agent just as the President travels to Oahu. Also, McGarrett's Aunt Deb visits, bringing with her a shocking secret.
Episode: 4x10 | Airdate: Dec 13, 2013
The attempted murder of a Pearl Harbor veteran leads Five-0 to use decades old evidence to investigate a deadly crime committed within the internment camps on Oahu during World War II.
Episode: 4x11 | Airdate: Dec 20, 2013
Chin's life is put in danger when a murder investigation reveals that the person behind the crime may be a serial killer. Meanwhile, Danny and Grace find a mysterious puzzle box washed up on the shores of Oahu.
Episode: 4x12 | Airdate: Jan 10, 2014
McGarrett helps Grover investigate his friend's disappearance after he apparently commits murder. Meanwhile, Kono continues her search for Adam.
Episode: 4x13 | Airdate: Jan 17, 2014
Internal Affairs questions Chin about his father's murder 15 years earlier and how his then-new relationship with Malia and her family might have hurt the investigation.
Episode: 4x14 | Airdate: Jan 31, 2014
McGarrett and Danny are kidnapped by an escaped convict who wants Five-0 to prove his innocence. Meanwhile, Danny must deal with Grace after she punches someone at school.
Episode: 4x15 | Airdate: Feb 28, 2014
While Five-0 investigates the murder of a real estate agent whose body was found in the walls of one of his listings, Danny is thrown when his mother comes to Oahu with shocking news.
Episode: 4x16 | Airdate: Mar 7, 2014
Five-0 investigates a triple homicide connected to a downed top-secret Chinese satellite, while Grover takes Danny's mother on a ride-along.
Episode: 4x17 | Airdate: Mar 14, 2014
Five-0 aims to uncovers the sordid truth when a girl is taken from her home and her father is shot in the process. Meanwhile, Danny tries to get his parents back together and Jerry deciphers a code he found on the bottom of McGarrett's champ box.
Episode: 4x18 | Airdate: Apr 4, 2014
Five-0 investigates when the daughter of a macadamia nut tycoon is murdered with a stiletto heel during Chin's high school reunion.
Episode: 4x19 | Airdate: Apr 11, 2014
Five-0 is set up when a bad tip leads them to an abandoned building that is rigged to explode with McGarrett and Danny trapped inside.
Episode: 4x20 | Airdate: Apr 25, 2014
The investigation of a murdered pool cleaner leads Five-0 to uncover a possible terrorist cell of radicalized students who are plotting an attack on U.S. soil.
Episode: 4x21 | Airdate: May 2, 2014
McGarrett and Catherine travel to Afghanistan to stop the Taliban from harming a young boy whose family saved Catherine's life years ago.
Episode: 4x22 | Airdate: May 9, 2014
When Grover's daughter is kidnapped by an old nemesis, he is forced to help steal $100 million in order to get her back. Meanwhile, Wo Fat escapes prison and heads back to Oahu.