Stabilized

Background
When first visiting Riften, Shadr and Sapphire will be having a conversation and can be overheard. Listening to the conversation reveals that Shadr is indebted to Sapphire, who is intimidating him and verbally attacking him for not paying her yet. Shadr explains that he was not able to pay her yet because the shipment of goods he had coming in was attacked. Further listening reveals that it was almost certainly Sapphire herself who attacked the caravan and stole his shipment, she does not admit or deny the claim (though her behavior sugguests she really did do it). Even in light of this she still demands his payment "or else". Sapphire will then leave and walk into The Bee and Barb and Shadr will sit down on a bench placed on the bridge that the conversation took place on.

The conversation
Listen in on the conversation between Shadr and Sapphire. There is no actual quest log entry and this does not start the quest, but it is a part of the backstory and is the easiest way to start the quest as Shadr's location will be known. Only during the first visit to Riften can this conversation be overheard.

After listening to the conversation, speak with Shadr. Shadr will explain his situation and the fear he has for his own life. Offer to assist him, he will seem very greatful. Now there should be a quest log entry under Miscellaneous

Missing the conversation
Upon entering Riften for the first time, if the conversation was missed from not sticking around, Shadr will no longer be sitting on the bench at the bridge. Shadr can usually be found at Riften Stables (where he works and lives) or walking around the lower docks of Riften (the same level as The Ratways entrance)

Speak with Sapphire
Head to The Bee and Barb, right at the entrance Sapphire can be seen leaning against a corner section of the wall. There is several different ways of dealing with Sapphire.
 * 1) Pass a Speech skill check. Persuade or Intimidate Sapphire. This reveals that she indeed did have the caravan attacked. She will then come to the realization that she has already made enough money off of Shadr and she backs off.
 * 2) Pay Shadr's debt. If the Speech skill check cannot be passed, his debt can be outright payed off with sixty seven septims.
 * 3) If having already became a member of the Thieves Guild, Sapphire will offer a fifty fifty cut of the gold made off of Shadr.
 * 4) If having already been appointed head of the Thieves Guild, Sapphire will recognize her boss and will apologize about the situation with Shadr's debt. She will go on to explain further that she had intended to speak with Delvin about cutting the guild in on the profit. Afterwords there is two choices
 * 5) *Tell her to forget all about Shadr's debt. She will follow the orders of her guildmaster.
 * 6) *Split the profit made off of Shadr

Return to Shadr
No matter what option was selected, the quest will continue into another conversation with Shadr.

If Sapphire was convinced to leave Shadr alone was chosen, Shadr will be very greatful and will then become a friend. He will show this by rewarding the kind deed with a leveled invisibilty potion, and will allow you to borrow a horse from Riften Stables.

(To borrow a horse, simply approach the horses outside, if it says steal in red letters do not get on that horse, go to another until it says "Ride Horse" in white letters, this is free and can be done several times in the future, however upon dismounting the horse it will return to the stables as it is not owned)

If the option to get a cut of the gold made off of him is selected, return to Shadr and tell him there was no way to convince Sapphire to back off. Return to Sapphire and get the gold payoff.

Bugs

 * When attempting to speak with Sapphire, the dialogue window will not open. She will just say "I have no business with you" every time an attempt is made to speak with her.
 * Completing the Thieves Guild questline might fix the issue
 * The speach bug with Sapphire may occur because when first speaking with Shadr the offer to help was not made, and was then made later after a second time speaking with Shadr. If this was the case the following fix may work
 * To fix this, reload a save that was before speaking to Shadr and then try again, the problem should be resolved
 * Another fix to this problem (regardless of cause) is through the console. Use these two commands on Sapphire
 * addfac 19809 1
 * setrelationshiprank player 4
 * After, speak with her while wearing the Amulet of Mara; this will force a dialog with her.