I have implemented a new quest as my showcase.
Kephat Rangidil, the son of a prominent noble family, has been sent into hermetic exile for one year to get over a skooma addiciton. With his year in confinement almost at an end, he suddenly stops corresponding with his dear friend Dara Thiralas. Dara Thiralas sends the PC to check in on Kephat to make sure nothing bad has happened.
All the relevant NPCs are standing around in the Balmora open square (on the opposite side of the river from Caius Cosades's house) for your questing convenience.
Speak with Dara Thiralas to get the quest hook. You can choose to refuse to help which ends the quest.
Once you have agreed to help, checking the body of Kephat Rangidil will allow you to report that he has died of a Skooma Overdose. Otherwise, looking in the nearby chest will prompt you to investigate further (which, unbeknownst to the player, offers a better reeard).
If you decide to investigate further, speak to Kephat's Brother, Olas, with a high enough disposition to learn that it was Olas who sabotaged and poisoned Kephat. You can still choose to say nothing to Dara and claim that Kephat died of a simple overdose, or you can nark on Olas and tell Dara the truth, which gives you a better reward.
Alternatively, you can ask the Khajiit Slave Dro'Jurrzo about the whole ordeal. If you find the key (which is laying on the ground between them) and let Dro'Jurrzo @go free#, he will let you in on the secret that Olas ordered Dro'Jurrzo to bring Kephat the poisoned skooma and a forged note from Dara. You can then confront Olas without having to make nice with him.
The reward is a 1-year Skooma Eater's Anonymous coin which provide 25% or 50% Resistance to Poison depending on whether you told Dara of Olas's involvement or not. Dropping the coin removes the buff but it does not need to be worn, only left in the inventory.