1. "Call Sill" in Paris College.
2. "Ask" her about "Hikari" twice.
3. "Assault" Sill to learn a spell (whatever you want). Refer to the table provided above for known combinations.
4. Go to the Castle Gate. The guardian girl won’t let you in, as you need a “Castle permit” to get into the castle.
5. Return to the Park to trigger an event. There is a girl who seems to have lost her wallet. Choose to "Help her", whether you ask for a reward or not will not affect the result.
6. Go to Paris College. "Call Sill" and "Ask" her to spare some "Gold". Rance obtains 150 Gold.
7. As it is evening, the Inn is now open. Go there, talk to Nami, agree on staying overnight. You can "Negotiate the price" to reduce the cost.
8. In the Inn, “Call” Nami and keep "Talk"ing to her till she mentions something about thieves' increased activities and their crimes. Go to "Sleep".
9. Go to the Item Shop. The shop girl here will tell you about a hacker who provides a lot if information.
10. Go to the Info Store to meet said hacker. "Ask" her about anything you want, she will tell you that you need to buy the information to earn one.
11. Go to the Pub and talk to the bartender (you will most likely meet Sill along the way). "Ask" the bartender about “Castle Permit” and then “Thieves”, He will tell you that his daughter got kidnapped by them and will ask for your help. Rance obtains 800 Gold.
12. Now you have enough money, go buy some weapons in the Armor shop. It's recommended to pick the highest-tier ones for easier battles.
13. Return to the Info Store. "Buy Information" about "Lair" to know how to enter thieves' cave and its location. It will cost you 200 Gold, but you have to buy it in order to progress with the story. The hacker girl will offer you an additional info by 100 Gold, feel free to take it if you still have enough money.
14. Now step outside the city through the Entrance Gate. "Look for monsters" and defeat them to earn experience point as much as you can to be safe for the later play-through. You need to visit Level Room which located in the Main City to "Level up". You need level 12 (no more, no less) to get Haniwa bronze statue. Once you feel that you are strong enough and well prepared, get inside the Thieves' Lair through Zone 3.
(assuming you used the highest-tier weapon/armor, it's recommended to "Look for monsters" in Zone 3 as most of them give you a good amount of experiences and safer)
Note: If you want to get Haniwa bronze statue you have to ask Item Shop Girl about monsters again.