As mentioned the lead will be using a microcontroller so Video surveillance is out.
Now what we can do is use motion sensors. If the shop is an average one then number of motion sensors usage will be less. The controllers will be connected to both GSM module and the sensors.
As soon as any distubance is detected the microcontroller will trigger the gsm and send a message or something to the owner. OR what we can do is to connect the gsm to a server which will process the data (if there is a breach disturbance) and accordingly set the alarm on the owner’s phone. The app will always be polling the server state (Dont know much about the app though) and as soon as something happens the app will get an alarm code and start to buzz/alarming sound on the phone itself so as to wake up the owner even when he is in deep sleep.
There will be other “features” to it viz sending sms, calling police(dont know if it will work), calling out to the security guard (chowkidaar kind of) or something like those.
The implementation is simple and could be done using parsing the gsm data.
If there is other motion detection scheme then the best one will be chosen.