In addition to what Abhi posted above.
Any of the Older Unsegmented & Segmented Stories that available in the shop to purchase for either 100 or 500 gems......you can repurchase & replay these stories as many times as you like.
The game scenes/mines & quests will be reset to the beginning on subsequent play throughs.
However the Trophies & Achievements will start off where you last left them....so if you fully completed them on your 1st play through you will not be awarded again for the Trophies & Achievements.
However you can still click on the where the Trophies would be throughout the game scenes/mines & you will get an experience bonus.
While there are Older Unsegmented Stories available in the shop for 100 gems it's a great time to do these stories.
Some of these Older Unsegmented Stories actually give back more than 100 gems on your 1st play through.
There is a spreadsheet on this Wiki page that shows the number of gems that can be gained from the Older Unsegmented Stories that cost 100 gems
The gem counts on the 100 gem sale Older Unsegmented Stories spreadsheet in the relevant Wiki page.....do not include the potential double rewards that can be received on the 1st time play through Achievements (assuming that the double rewards actually work properly).
I have created some spreadsheets in relation to the camp equipment available in the Older Unsegmented & Segmented Stories...you can check them out in this link below...if you are interested