You get the mission "Dark Temptations" after completing the mission "The Face of the Enemy"
Open your mission log:
Dark Temptations
Master Orgus has learned of several Flesh Raider bases scattered about Tython. He has instructed you to deal with one located in the Kaleth Ruins. Infiltrate the Flesh aider stronghold inside the Forsaken Den in the upper level of the Kaleth Ruins.
Go to the Ruins of Kaleth and enter the Forsaken Den. You encounter Laotah, a mortally injured Jedi Knight. He tells you that the Flesh Raiders took his lightsaber and warns you that they are skilled in the Force. Your task now is to recover Laotah's stolen lightsaber from the Flesh Raider bladewielder who stole it from him in the Forsaken Den of the Kaleth Ruins.
Head south in the cavern. On your way, complete the bonus mission "Scars of the Dark Side" by defeating 10 Flesh Raider Savage Adepts. Kill the Bladewielder and get Laotah's Broken Lightsaber. Use your holocom. Tell Master Orgus that the Flesh Raider camp's out of commission and that they were all force users. They killed a Jedi named Laotah. Orgus tells you that you will reclaim the fallen later. He just got a distress call from the Twi'lek settlement. They spotted Bengel Morr. You and Master Orgus are the only ones who can handle this. He wants you to meet him in the settlement.
Your task now is to hurry back to the Kalikori village and check in with Ranna Tao'Ven at the Matriarch's buildings. You tell her that Master Orgus responded to your distress call and you were to meet him here. She says that they did not send any distress call, things have been quiet since you left. She hasn't seen or spoken to Master Orgus. T7 scans the area and confirms that Master Orgus is not in settlement nor is he answering Holocom. Suddenly you get hit by a poison dart. Scout Chief Moorint tells Ranna that you have to die. Ranna asks them to leave you alone, that was the pact. Ask them what is going on. What did they do to your master, and where is Bengel Morr. Scout Chief Moorint tells you that Bengel Morr came to him and said he'd end the Flesh Raider attacks if they gave him your master. He also asked to kill you, but Ranna said no, that they'd keep you here. She asks Moorint not to hurt you, but Moorint insists that if they don't do what they are told, Bengel Morr will kill them all.
You can tell them that he will kill them all anyway (LIGHT), or try a [FORCE PERSUADE] of Go in Peace, or say that you have heard enough and attack (DARK). Afterwards, speak to Ranna. She tells you there is still time to save your master. Bengel Morr took Orgus to someplace called the Forge. Reactivate your droid, it might know where to find them. Speak to T7. Tell him that Bengel Morr took your master to someplace called the Forge and ask him if he knows where that is. Use your personal holocom to contact A-4PO, Jedi Archivist. Tell him to transmit everything you know about the Forge to your droid T7. He will tell you that the area is considered highly dangerous and asks you why you need that data. Tell him it is an emergency, Flesh Raiders captured Master Orgus and took him there. He will tell you that the timing is not good because the temple Masters are all indisposed fighting Flesh Raiders. He will alert them immediately, but they will be unable to assist you. He transmits the data to T7.
Your reward will include the choice of a T7 customization for you companion. You can CTRL + Left Click on the item and then click on the "COMPANION" tab to preview it on your companion before choosing.
This completes the mission "Dark Temptations" and begins the next Jedi Knight class mission, "Weapon of the Jedi".