He started appearing a month after… his death. She didn't notice him the first few times because he was simply in the background and she was still mourning. She's still mourning.
It was her fault that he had died.
It wasn't until the hairs in the back of her neck prickled two months after his death that she noticed that he was watching her.
He would watch her as she was walking into her school building. When she left her high school and when she entered her house.
He was there at his funeral.
Nobody else seemed to notice him. Sam noticed this three months after his death. The boy (man? She couldn't tell) had pure, messy white hair and beautiful, yet eerie green eyes that seemed to glow. There was something distinctly familiar about him, but Sam couldn't put her finger on it.
He wore a black hoodie that seemed to suck in all light and dark, black skinny jeans. If she wasn't still mourning over his death, she would have found the tanned stranger that was so familiar rather handsome. And completely her goth style.
But she didn't, because all she could think about was how her best friend and crush wasn't with her and Tucker anymore, and it was all her fault.
The white-haired stranger seemed to follow her everywhere, though. If she looked out of the classroom's windows, she would see him staring at her general direction. He was always there.
One day, Sam tugged on Tucker's arm and pointed to where the stranger was standing outside.
"What?" Tucker asked.
"Haven't you noticed him?" Sam asked.
"Noticed who?"
Tucker looked in the direction Sam was pointing and said,
"Your mind must be playing tricks on you, Sam. Nobody's there."
When she realized that no one else could see the stranger, Sam was officially frightened. Whenever she saw him, she would look away and pretend he wasn't watching her.
It was all for nothing, though, because once she decided to ignore the other being's presence, her instincts and senses seemed to suddenly heighten. She sensed the stranger everywhere. She couldn't find any sort of sanctuary from that gut-feeling of being watched, her skin was constantly covered in goosebumps, and she was often extremely cold, even when other girls were starting to wear tank tops and shorts.
It had been a year since Danny's death when she finally came to terms with the idea that she was being haunted. Nobody else could see the familiar stranger, who had decided to pop up more often.
Instead of keeping his distance the way he had at the beginning, Sam's ghost had decided to follow Sam everywhere she went. He followed her into her classes. He followed her to the Nasty Burger whenever she went to hang out there with Tucker. He followed her to her home and watched her as she slept.
Sam had tried to communicate with the spirit, but the ghost was decidedly mute. He kept an empty expression as he watched her, and his once beautiful but eerie green eyes became a haunting nightmare to Sam.
Tucker was very concerned for his remaining best friend. She had taken Danny's death the hardest out of all that cared for him. He was still in mourning, but was just starting to move on.
Sam, however, could not seem to get over Danny's death. Tucker knew she blamed herself: everyone knew it. Jazz had even asked Tucker to take care of Sam, because she had practically skipped the second and third stages of grief (anger and bargaining) and went straight from denial to depression.
But the depression had stayed for years.
By the time Sam and Tucker were seniors in high school, Tucker had accepted that Sam was being haunted (she had explained the familiar stranger to him) and Sam was used to being followed by her shadow that nobody noticed.
The stranger seemed to mature with Sam. He went from being an almost adult to definitely grown up at the same pace that Sam grew, but no matter how handsome the spirit was, he always managed to creep Sam out with his glowing, but empty, toxic green eyes.
Sam was working on her final English project when the spirit spoke for the first time.
"Sam."
Sam gasped and jolted from her laptop and turned around to see her haunter staring at her more intensely than he ever had before. She gaped.
"Sam."
The being repeated her name.
"Why are you haunting me?" Sam cried out. "Why won't you leave me alone? For nearly four years you follow me and only now you decide to speak? Why?"
"Sam!"
"Stop calling me that! You sound like…"
Sam collapsed as she realized why the echoing voice seemed so familiar, why he was so familiar.
"Danny?" she breathed out in less than a whisper.
"Sam."
"Can you not say anything more than my name? Are you or are you not Danny?" she demanded.
The phantom was silent, before saying one word.
"Come."
The spirit walked through Sam's door. Sam quickly wrenched it open to follow the being that could be Danny and ran towards him, following him. He lead her down the stairs, through the kitchen, and to the front door.
"Where are you going, Sammy-kins?" Sam's mother asked in a stern voice.
"I'm going for a walk, mom, I'll be back by dinner."
Sam ignored her mother's guffaws at Sam's rude reply, following the ghost that had haunted her outside.
She followed him until they reached what used to be FentonWorks.
Shortly after Danny's death, Jack and Maddie Fenton had decided to stop pursuing ghosts, since their greatest invention had killed their beloved son, through electrocution and overexposure to ectoplasm. As soon as the first semester of school had ended, the Fentons had packed up and left Amity Park, only returning twice a year to remember Danny and pay their respects to his gravestone.
FentonWorks, however, had not been inhabited ever since. The place had a reputation for being haunted, for obvious reasons.
Teenagers that didn't know the Fentons very well had a habit of daring each other to go in FentonWorks. The building was left unlocked, since not very many people managed to brave through the front hall, nevermind going deeper into the house to explore what truly could be haunted by the ghost-hunters' deceased son.
Many people claimed to hear whispers, rustling, or the occasional screaming whenever they braved to enter the house, which became the winning argument that the house was indeed haunted.
This was where Sam's haunter lead her. She hadn't been to FentonWorks since the day he died.
The ghost walked through the front door, and Sam followed. The specter walked to the kitchen to the door that lead to the basement.
This was where Sam stopped.
"No. I can't- I can't! I can't go in there!"
The being stopped walking and turned around to face Sam.
"You must."
Sam noticed that the ghost's body seemed to be glowing with its own aura, which was a pure white. His green eyes weren't just glowing, they were radiating. They were unnaturally providing a greenish tint in the lighting around the dark room, the lighting which Sam just noticed was coming from him.
"I-I can't. I can't go down there." Sam's eyes were pleading. She knew it, but she didn't care if it made her feel weak.
The ghost walked up to her, his steps never making a sound. The two were nose to nose (chin to nose, the ghost was undeniably taller than Sam, but their eyes never broke contact) as the ghost spoke,
"You will."
Sam was terrified. Her chin trembled, her body shook, and tears began to make their way out of her eyes.
"Please- don't make me…"
The ghost touched her for the first time, grabbing her left wrist with his right hand (which was ice cold) and started dragging her to the door to the basement where he died.
Sam struggled all the way, but the other-worldly being was much stronger than her. Before she knew it, they were at the bottom of the stairs and facing her was the empty hole that was the cause of her best friend's death.
Sam's knees gave way and she would have fallen to the floor had a strong arm not been holding her up. Sam's eyes could not hold the salty tears in any longer and they fell freely from her eyes down her cheeks.
"I'm sorry… I'm sorry, Danny, I'm so so sorry…" she wept.
The phantom slowly lowered so that he was kneeling on the floor. Sam fell with him and started bawling into his shoulder, gripping the hoodie that seemed to suck in all light and hope like a black hole. The ghost simply wrapped his arms around her in an attempt to comfort her, but his cold body could only do so much.
The two knelt there for a good half-hour until Sam had no tears left. The white-haired Danny moved Sam's body away from his shoulders and held the girl's cheeks in his palms, wiping away the remaining tears with his thumbs and the snot with his sleeve. His intense green eyes seemed to stare at Sam's very soul as her gaze met his.
"Don't blame yourself."
Sam hiccupped before replying hoarsely,
"But it's my fault you're dead… I'm the one who convinced you to go into the portal… if I hadn't done that… you'd still be alive..."
Danny's finger slid over to Sam's lip as he shushed her.
"Don't. I don't blame you, you shouldn't either."
Sam couldn't help but notice Danny's aura grow brighter as he said this.
"Danny…" she whispered.
The girl threw herself on to Danny and crushed him in a hug with all the might she could. Danny returned the hug equally and grew brighter as he did so.
"Why didn't you talk to me sooner?" Sam asked, still hugging Danny as tightly as she could. She wouldn't let go of him until he let go of her.
"You weren't ready. And… I wasn't ready either," Danny admitted sheepishly. Sam wondered how she didn't notice that her haunter of nearly four years was actually Danny.
"Why now, then?"
"My time was, is, running out. It won't be long now before I have to move on."
"What?"
Danny pulled away to meet Sam's lilac eyes.
"There's… a higher Being in charge of all… this. Life, death, life after death. I knew you wouldn't take my death very well because of the circumstances, so I begged to be able to stay behind just a bit longer so that I could say goodbye. I wanted to say bye to Tucker, and Jazz, and Mom and Dad, too, but for some reason, only you could see me. I don't really know why." His brows furrowed as he admitted his ignorance to why only Sam could see him. "Point is," he continued, "I don't want you to continue blaming yourself for what happened to me. I want you to keep living. You still have so much ahead of you, so much to live for, and I don't want you to let all of that go." Danny gave Sam a goofy, lopsided smile before kissing her on her brow.
"Take me with you!" Sam cried out before throwing her arms around him again. Danny didn't hold on to her as tightly, instead, he ran his hands and fingers through her raven hair.
"I can't. Didn't you hear what I just said?" Danny chuckled, pressing another kiss to the crown of her head. His aura grew brighter and brighter. His clothes bled from the darkest black to the purest white.
"You still have purpose here. Don't give it up so quickly. You have loved ones waiting for you, and a wonderful life ahead of you. I'll still watch over you. And Tucker, and Jazz, and Mom and Dad."
Sam started to sob again, but she eventually let go. Danny's body was so bright it was hard to look at, and it was only growing brighter.
"I love you, Sam."
Sam choked, before replying,
"I love you too."
Through the bright light, Sam could barely make out Danny's smile before he disappeared in a blinding flash.
Blinking the dark spots away, Sam looked around, hoping to catch some sort of sign that Danny was still there, but the lab was empty.
For a few minutes, Sam contemplated going into the portal and joining him, but decided against it when she realized how disappointed Danny would be if she didn't respect his wish for her to live.
Sam stood up from her spot on the floor and walked to the stairs going up to the kitchen, turning around one last time to look at the place where Danny had passed.
A small smile graced her lips as a single tear descended to her jawline before turning to the stairs and leaving the house forever.
As Sam walked home, she looked up to the dark sky, and vowed,
"I'll live, Danny, for you, for Tucker, and for my parents. But I'll never forget you, I promise."
Sam never returned home that night. Her parents called the police, and a search was instigated.
Sam's body was found in a ditch the next morning, with cuts and bruises all along her arms, legs, neck, and face. The rapist who murdered her was captured and put on trial with a sentence for life for rape and murder.
Tucker was heartbroken at the news of his last best friend's sudden and violent death. After mourning Sam's death for a year, he found new friends (they weren't Danny or Sam: nothing could replace them) and became a professional hacker for the CIA. He found life again.
But somewhere, beyond death, two beings were reunited, and they lived.