Nidhi and An Intruder puzzle

Nidhi was sitting at her study table, home alone, on a cold and stormy night. She was reading her books when she heard faint footsteps. Nidhi got out of her room and looked around when suddenly, without warning, she was grabbed by the neck. She tried to scream but it came out as a mere whimper as the intruder was pressing hard against her throat with his arm. 

"Give me all your money!" growled the man who had grabbed her from behind.

"Th-there is none h-here! Please ll-let me go!" cried Nidhi.

"Don't LIE TO ME!" screamed the increasingly agitated man. She felt the man strengthen his grip around her neck. She said nothing and a few seconds passed by in silence. 

Suddenly the phone rang which alerted both of them.
"People will get suspicious if I don't answer the phone," said Nidhi, with a controlled voice. The intruder let her go.

"Alright, but NO funny business, or ELSE!" said the nervous intruder. Nidhi walked toward the phone. She took a deep breath and calmed herself. She picked up the phone.

"Hey Sona. Thanks for the call. Hey you know those Science notes I lent you last week? Well I really need them back. It would be a great help to me. It's an emergency, so if you could give me them tomorrow it would be great. Please hurry in finding the notes. I need to get back to my books now. Bye," Nidhi said. She hung up the phone.

"It was wise of you not to say anything," said the intruder, although he was more than a bit confused by her conversation.

"Now TELL ME WHERE THE MONEY IS KEPT!" screamed the thief.

"It...it's...in my dad's room. The first room on the right. Third drawer," said Nidhi.

"SHOW me!" said the man, and removed his grip around her neck. She took a big gulp of air and nearly fell. She swallowed hard and said a silent prayer. She walked slowly, in silence, toward her father's room. All of a sudden, they heard police sirens. The intruder froze in his footsteps. He ran to the nearest window and jumped out of it.

Nidhi ran outside in time to see the intruder being escorted into the car. She saw Sona and she ran toward her and hugged her.

"Smart kids," said the policeman.

What had happened?


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