A possible concise summary is:
This is a story about two sisters, Iris and Chloe, who are always fighting and competing with each other. Their dad sends them on a treasure hunt to make them bond, but they encounter two thieves who try to steal the treasure. The sisters work together to escape and realize they love each other. The treasure turns out to be a picture of them as babies.
Here are the key facts extracted from the text:
1. Iris and Chloe are sisters who have been fighting since they were kids.
2. Their dad is a university professor who lost his job after a mishap at Iris's birthday party.
3. They moved into their grandma's house, which was supposedly haunted by a pirate.
4. Elton, a boy who lived across the street, befriended Iris and gave her a treasure map that belonged to their grandma's uncle.
5. Chloe got jealous of Iris and Elton and tried to get his attention by flirting with him.
6. Elton turned out to be a thief who wanted the treasure for himself. He had a twin brother who helped him rob houses.
7. The treasure was actually a picture of Iris and Chloe as babies, which their dad hid to make them bond and stop fighting.
8. Chloe texted their dad when they were in trouble with the Eltons, and he came with the police to arrest them.
9. Iris and Chloe became closer after their treasure hunt and started to help each other with makeup and studying.