Torn is about a RiverClan tom named Cloudkit. He only has one littermate, Briarkit, and she is blind. Being the larger and stronger if the two, Cloudkit naturally feels responsible for the safety of his sister. He stands up for her countless times, and helps guide her around camp. (This could either make Briarkit, who is an extremely sweet she-kit, upset or grateful, depending on the situation.)
As they grow to become apprentices, Cloudpaw can hardly stand to leave Briarpaw's side. He insists on going on every patrol with her so that he can protect her from potential dangers.
After a few moons of this, Briarpaw snapped. She yells at him, telling him to back off and give her some space. This emotionally devastates Cloudpaw, but also gives him more time to focus on his warrior abilities. He still tries to be around his sister, but doesn't get in her face as much.
Then, while he was at a Gathering, he met Silverpaw. She was a gorgeous silver tabby from WindClan with the prettiest blue eyes. Cloudpaw instantly fell head-over-heels for her, and followed her around all night. When the night ended, Silverpaw pulled him aside and simply whispered, "Horseplace, in two nights. Be there."
The two met in secret for a while, until the strain of being awake all day and night started to overwhelm him. He finally confessed what had been going on to Briarpaw, who had been growing suspicious of him. She was rightly furious, and demanded he stop seeing Silverpaw. A heated argument ensued, and ended with an enraged Cloudpaw swiping at Briarpaw, claws unsheathed. He left a decent-sized nick in her ear, and sent her to the medicine den.
Cloudpaw's life is a mess, and it only gets worse when he is given his warrior name, Cloudtuft. His mate, Silverflame, suggests for the first time that he come to WindClan. He politely declines, until she blurts out that she's pregnant. His heart sinks. He knows he can't leave his Clan, his kin, and his sister, but he wants to be with his mate and kits so, so badly. He tells Silverflame to meet him back at the Horseplace in a quarter moon, and he'll tell her his decision.
After many sleepless nights, he decides to move to WindClan. He doesn't tell anyone in his Clan, not even his sister, Briarthorn. He and Silverflame live happily together until the next Gathering, where Briarthorn confronts him. As it turns out, she is carrying a tom's, Eagletalon's, kits. Cloudtuft feels terrible for abandoning her, and a second heated argument takes place, in front of all the Clans. RiverClan banishes Cloudtuft from ever entering their territory again, but WindClan turns a blind eye to the whole situation.
Everything is fine until word gets out that Briarthorn has caught deadly greencough. Cloudtuft can't take it anymore, and runs back to RiverClan in the middle of the night, leaving Silverflame, Acornkit, Falconkit, and Quailkit behind.
After some negotiation, RiverClan begrudgingly accepts Cloudtuft back into the Clan. Briarthorn is elated, and ends up recovering from her sickness and giving birth to two healthy kits; Troutkit and Flamekit. Cloudtuft requested that the small, dark ginger tabby she-kit be named after his mate, whom he would likely never see again.
Cloudtuft's kits despise him, but Silverflame is more hurt than angry. They meet in a few border patrols many moons later, and insults are spat with claws unsheathed. They avoid a battle, though, and Cloudtuft manages to convince them that he did the only thing he could. Acornpaw, Falconpaw, and Quailpaw still retain a small amount of anger, but they are glad to hear that their father still cares for them. Cloudtuft is now content to watch his kits grow up from afar, though he wishes that things could have been easier, for him and his family.