Chapter 1: Trunks' anger
Trunks was absolutely livid when he found out that the androids had hurt his master, Gohan. As he watched over his training sensei who was resting in a medical bed with bandages around him, Trunks made the decision to leave the scene and try and train to become a Super Saiyan himself.
Bulma, Trunks' mother, was at his side as she worked away at the time machine. Taking off a few moments to check up on Gohan before looking back to the device, Bulma was the only one who noticed Trunks had left. 'Where is he going?' she whispered, worrying that her son was about to go off on a vendetta against the androids.
She was proved right when she followed the sound of energy to a nearby clearing minutes later. Here she found her son, having gone to Gohan's usual training area, screaming out of frustration as he thrashed his fists around. He had already punched so much that there were many holes and cracks in the ground from the energy of his fists.
'Trunks!' Bulma shouted, trying to get her son's attention before he suffered a serious injury. He paused from his thrashing, lifted his head and looked at his mother. 'What am I even doing mother?' he asked, now exhausted from all his effort.
Bulma simply shook her head and walked over to Trunks, wrapping her arms around his shoulders comfortingly.
'What if I could become a Super Saiyan like Gohan,' Trunks said, slowly regaining his energy. With that, the boy began to charge up his power and embrace his inner anger. For a few tense seconds, there was a bright yellow light that lit up the clearing and suddenly, Trunks had achieved the form for a few seconds.
Bulma was blown away to see her son had managed to reach this powerful form. After composing her emotions, she walked over to Trunks and placed an arm around his shoulder in an embrace.
'If Gohan was awake right now, he would be proud of you, my son.' She said those words and every fiber of Trunks' being felt at that moment. He knew that his master was the source of his strength and that if he could get into the form and sustain it for more time then he could possibly take his training to the next level.
And right there, the little saiyan began to take initiative by practicing and training every day. He got determined to master his new form and reach a level of power where he could take revenge on the androids and uphold his master's legacy.