Guide to Ptolus
Since the party s going to appear in the city in the Undercity market and as there is a guide service there, it's a good bet the players will afford themselves of this service. It is also expected that the guide will have dealt with "foreigners" and newbes before and have a spiel all ready for them. Remember, he is employed at their leisure and the longer he can string out his gig, the better it is for him. Therefore he will do a lot of "well if we have time tomorrow we can take a closer look at that" and even more of "there is a wonderful story about that building, but it will have to wait until later if we expect to finsh our tour".
He is a human that looks about 15 but is really in his 20s (23). He acts like a child in order to mislead his patrons and ease their suspicions allowing him a better chance to rip them off if he wants to. He is small and slight (111 lbs) with blunt features and an open face. His hair is in a "bowl cut" and he smiles a lot. He is thinck with the Undercity thieves and owes them a cut of whatever he makes either with the guide job or with the theft if he thinks he can get away with it.

Solvi Yektya, male human Rog2:  CR 2; Size M (5 ft., 5 in. tall); HD 2d6+2; hp 12; Init +2 (+2 Dex); Spd 30 ft.; AC 12 (+2 Dex); Attack -2 melee, or +3 ranged; SV Fort +1, Ref +5, Will +4; AL N; Str 4, Dex 15, Con 12, Int 11, Wis 18, Cha 11.
Languages Spoken:  Common.
Skills and feats:  Appraise +1, Bluff +4, Decipher Script +3, Disable Device +5, Disguise +2, Gather Information +5, Hide +6, Knowledge (Local) +4, Listen +8, Move Silently +7, Search +4, Spot +9, Tumble +4; [Evasion], Magical Aptitude, Persuasive.

Assuming the party will hire one out of the undermarket, here is an itinerary for what the guide will take them to.

"Here is the Undercity market. It is a great place for delvers to buy the stuff they need to investigate the fell areas that are below the ground of the city. There are dozens and maybe hundreds of miles of rooms and passages that have never been discovered. The delvers make their living by locating them and removing the fell creatures there by making the city safer from the evil that threatens at all time to overwhelm the people above who go about their lives unknowing and uncaring that the land they walk on is beset by terrors beyond their imagination."
"Ptolus has become a city of adventurers. Treasure-seekers flock there to explore and plunder the labyrinthine structures beneath the streets, which they call the “Dungeon.”

Some of Solvis patter:
"Ptolus is a major city of about seventy-five thousand people."