|Spoiler warning: Plot and/or ending details follow.|
It starts out in Midnight when Squirrelpaw insists on going with Brambleclaw to the sundrown place. on the journey the two cats become very close.
In Starlight, Squirrelflight begins to distrust Brambleclaw because of his intrest in his half-brother Hawkfrost. They quarrel often through the book, each fight bringing them farther apart. They finally make up with each other during the badger attack in Twilight.
In The Sight Squirrelflight has three kits, Jaykit, Lionkit and Hollykit, though they are not theirs. During the fire in Long Shadows, Ashfur blocks the escape for Jayfeather Lionblaze and Hollyleaf, making Squirrelflight reveal they are not her kits. When The three cats find out that there parents are really Leafpool and Crowfeather, Hollyleaf, unable to bear it reveals it at the next gathering. Brambleclaw, who never knew that they weren't his kits, gets mad at Squirrelflight, saying that he could have helped hide the truth and stops being her mate.
In Sign of the Moon, before going to the mountains, Squirrelflight asks if Brambleclaw had any thing for her to pass on to Stormfur and Brook. She asked the question to see if Brambleclaw had any feelings for her, but his answer confirmed he didn't.
Brambleclaw- Bramblepaw Bramblekit
Squirrelflight- Squirrelpaw Squirrelkit