It says it on the title

When Alexis agrees to help the school's player, she must guard the secret that could unravel everything - even as unexpected feelings complicate the game. *** What happens when Alexis Dawson, the 'resident loser' of Redwood High, agrees to help the school's notorious player, Aaron Walker? How can she stop herself from falling for him? It isn't all love and romance - Alexis has a secret of her own. Join them on a journey of jealousy, betrayal, trust, friendship, and love. A little favour just got a whole lot more complicated. *** He was so close, his breath hit my lips. His eyes darted from my eyes to my lips. I stared intently, awaiting his next move. His lips fell near my ear. "Shut up and kiss me" He whispered roughly. A chill shot up my spine. I pulled back, staring at his eyes and leaned in...

"Okay, so technically this was his fault. He started this war with her a couple weeks ago, and honestly, he could pinpoint a few moments when it turned into dangerous territory. They were flirting, heavy, and at first it was just to piss Sam off, but suddenly it was happening when Sam wasn't around." Bucky and Sarah find themselves venturing beyond the lines that were drawn out. Very Very Mature theme. Explicit, and definitely not suitable for certain audiences.