Since always mankind has been interested in unveiling the mysteries of our Universe. I am searching for answers using gamma ray astronomy. I am studying the non-thermal Universe where extreme environments produce gamma-ray emission at very high energies. These environments cannot be reproduced on Earth. To study such high energies, we have to observe the outer space. I focus my research on the mysteries of Transient objects in our Universe. Transient sources are characterized through their unpredictable emission on timescales spanning milliseconds to years. They are associated with extreme events involving relativistic compact objects such as neutron stars, black holes, and violent explosions in the Universe, known as Gamma Ray Bursts, which manifest the most extreme physical conditions in the Universe.