05.20 Episode 108
Airdate: May 3, 2002

During the operation of NID off-world teams, Colonel Grieves and Lieutenant Kershaw had visited Latona in an attempt to steal the technology for the Sentinel, a defensive weapon capable of protecting the entire planet. Since then, Grieves and Kershaw have been convicted of high treason, and SG-9 has tried to restore diplomatic relations with the Latonans. However, the planet is now under attack by Jaffa forces, and the Sentinel fails to activate. The earlier NID mission may have disabled the device, rendering the planet defenseless, and SG-1 must find a way to rescue the Latonans from attack.

O'Neill visits Grieves in prison, but Grieves insists that the Sentinel is undamaged, and he demands that he and Kershaw join the return mission to Latona. On the planet, Grieves and Kershaw begin the process of breaking the code to the force field protecting the Sentinel, while O'Neill goes to the city to meet Marul, the Latonan leader, to convince him of the danger. The planet is overrun by Jaffa patrols, but Marul has complete faith that the Sentinel will not fail to protect his people. Even as Svarog's mothership attacks the planet from the air, O'Neill cannot convince him to evacuate.

The Latonans have technologically regressed since the Sentinel was built long ago. No one knows how it works, but the Caretaker has always watched over it. When Daniel translates the symbols on the device as "Life Energy, Two as One," Kershaw recalls the Caretaker, a hermit encountered on their earlier mission. He had taken them by surprise, and Grieves had killed him. Now Grieves comes to understand the mysteries of the Sentinel. As Jaffa forces surround them, Grieves touches the device, two life forces, man and machine, joined as one, and the Sentinel activates. The Goa'uld invaders are enveloped in a blinding light, and vanish.

Written by: Ron Wilkerson
Directed by: Peter DeLuise

Guest Starring: Henry Gibson as Marul, Frank Cassini as Colonel Sean Grieves, Christina Cox as Lieutenant Kershaw, David Kopp as Lieutenant Grogan, Gary Jones as Technician, Colin Lawrence as Major Lawrence, Shawn Reis as Jaffa Commander, Carrie Ann Fleming as Assistant, Chris Newton as Caretaker

Reference: Caretaker, Sean Grieves, Lieutenant Grogan, Lieutenant Kershaw, Latona, Major Lawrence, Marul, Missiles, NID, NID Off-World Operation, NID Rogue Operation, Sentinel, Staff Cannon, Svarog, Torture Device, UAV