The classroom was bigger than Harry expected. The bell hadn't rung yet; he was the only student there, impatient to get started.

'Good afternoon, Professor,' Harry said, well-practised not to slip up with “Mum”.

'And to you, Mr Potter.' Lily smiled warmly, shuffling papers at her desk. 'Shouldn't you be at lunch?'

'I left early.' He winced at her motherly frown. 'I ate a sandwich and an apple.'

'Good boy.' Lily nodded. 'Help me set up?'

'Okay.' Harry put his books on a desk, dropping his bag by the chair. 'I had Potions this morning with Da...I mean, with Professor Snape. It was fun.'

'Fun?' She stared, passing him papers for each desk. 'That's not what I've heard.' Lily frowned with deep disapproval, but kept her gaze elsewhere so Harry knew it wasn't aimed at him.

'He was in a bad mood.' Harry shrugged, confidence slipping. 'But I liked making the potion. We brewed a cure of boils! Mine was exactly like the one in my book.'

'That's...' Lily paused, glancing at Hermione as the girl entered. 'Very interesting, Mr Potter. I'm glad you're settling in well.'

Harry sat at his desk, considering taking notes but didn't want to be accused of not paying attention again.

Lily was dressed in a blue cloak over black robes, which suited her better than a plain shirt and jeans. Having lived as a freak with the Dursleys, it was nice to be undeniably reminded that his parents did magic too.

'There you are,' Ron said, sitting beside him. 'I can't believe you got here before Hermione.'

'Professor Aster is going to teach us how to fight dark magic,' Harry said. 'Isn't that brilliant?'

'I guess.' Ron frowned. 'But she'll still give us homework. Loads of it, I bet. Percy's already going on about his OWLs and term's barely started.'

Harry closed his textbook, staring at the cover. Cheeks heated in embarrassment, he realised it wasn't normal to be excited for classes. Harry didn't even know magic existed until a month ago, and wanted to learn as much as he could, but he was being extra freaky about it. He should've waited in the Great Hall with Ron and everyone else.

Lily went over the roll, looking at each student who answered. Thankfully, she didn't pause at Harry's name like others had.

'Welcome, first years,' she said, 'to Defence Against the Dark Arts. Today we'll be discussing basic protections and defensive strategies. Who can tell me the three core categories of spells, and how they're different from each other?'

Hermione's hand shot into the air.

Harry took notes anyway. His dad brewed potions that saved lives and his mum fought bad forces that tried to take lives. If he could learn even a little of what they knew, Harry wouldn't be scared all the time. He could finally protect himself from those bigger and stronger than himself.

'A difficult obstacle doesn't always require an equally difficult solution,' Lily said. 'For example, who knows which presently simplistic and widely common charm wasn't even invented until the 18th century?'

Her hazel eyes, though emerald to Harry, swept around the room.

Harry glanced at Hermione's hoisted hand, and guiltily raised his own. She'd answered questions in each their classes so far, and he'd enjoyed knowing the right answer in Potions.

'Mr Potter?' Lily smiled and nodded encouragingly.

'Er – the Wand-Lighting Charm,' Harry said, remembering her emphasis on it while reading textbooks to him.

'That's correct. Five points to Gryffindor.' Lily nodded, leaning to sit on her desk. 'Light and darkness are both simple and complex. Their magics are no exception. The Dart Arts are ever-changing and unpredictable, and to combat them you must be equally so.'

Harry glanced longingly at his quill, ears intent on memorising every detail. He smiled, noticing the class was stilled and attentive; Lily received equal manner of focus as Professors Snape and McGonagall.

'Now, each of you have a scenario written in front of you.' Lily indicated to their desks. 'Your assignment for this lesson is to fill out the questionnaire regarding that scenario. Afterwards, we will practise wand safety and defensive manoeuvres. Any questions?'

'Bloody hell,' Ron muttered, reading his scenario. 'Why'd it have to be spiders?'

Harry sympathetically pat his friend's shoulder, and overturned his own paper. His glasses remained forgotten in his robes pocket. 

Scenario: You're in a forest, being chased by an angry beast who thinks you've threatened her young. 

Context: You'd accidentally walked too close to the well-hidden den, but caused no harm to the young. You have no friends or allies with you. 

Harry read over the questionnaire and started writing, imagining he was being chased by either Dudley or Ripper. He knew better than to attempt to fight or defend himself, choosing options to hide in a tree or confuse the beast.

'How do you know everything?' Ron glanced enviously at Harry's lengthy answers.

'I don't,' Harry said, hesitating. 'It's mostly luck. And I read books. Nothing special, I promise.'

He waited until Hermione and a few Ravenclaws handed in their papers before adding his own. Harry tried not to fidget, as Lily read through the results and picked a few to comment on.

'I'm most impressed with the detail against your Devil's Snare, Mr Longbottom. I'm sure Professor Sprout would be as well.' Lily smiled at the shocked boy. 'You've quite the aptitude for Herbology, like your mother.'

Harry turned properly to see Neville's eyes become misty. He'd heard of the Longbottoms in August, when Lily talked during dinner about how fun Hogwarts was. Frank and Alice were in Saint Mungo's, which is why Lily fought so hard to work there as a Healer. She promised to introduce Harry to them one day, but he'd forgotten Neville. Harry shared his dormitory with him, just as Lily had shared hers with Alice.

'When faced with a creature, many of you chose to fight,' Lily said, glancing over papers. 'There's no shame in running away. Cowardice and foregoing recklessness are not the same thing. Mr Potter recognised this, well done. And Mr Weasley, your strategy would have certainly worked.'

Harry and Ron shared proud relief, which lasted through the rest of the lesson. Harry initially thought Lily favoured Gryffindors, as Severus did Slytherins, but she deliberately found strengths in everyone – even Malfoy, who'd grimaced at the concept of Muggle fighting sometimes being more effective than fancy wand-work.

Harry slung his bag over his shoulder, lingering as he'd done in Potions. He waved Ron off, politely telling his friend not to wait.

'Just like at Saint Mungo's, if you ever have questions – my door is open,' Lily said kindly to Neville. 'I knew your parents well during our time at Hogwarts, especially your mother. They'd be very proud of you.'

'Thank you,' Neville said quietly, a look of awe on his face. He left the classroom, hugging a photograph to his chest.

Lily led Harry up the stairs to her office. There were empty tanks and covered cages to one side of the desk, and two softly blue armchairs around a small table to the other – by a tall window with scarlet drapes spread open.

She waved her wand; the door shut and Harry's skin tingled. 'Privacy charms,' she explained, offering tea as they sat across each other. 'Now, tell me all about your first week.'

Harry stayed the entire afternoon. The visit was dampened by nutrient potions she made him drink and then the subject of his sorting.

'And what were they?' Lily asked, with a strange expression similar to the one Severus gave him when mentioning the Draught of Living Death.

'Asphodel. Wormwood. Bezoar. Monkshood. Wolfsbane,' Harry recited, numbering them off with his fingers. 'Oh, and Aconite. But that was mine.'

'I see.' Lily glanced at her lap, but didn't explain.

Harry sensed there was more to his dad's test than initially understood.

He spared no detail about his Potions class, and forgot he wasn't used to sharing thoughts and fears with an adult. So when Lily asked why the Sorting Hat took such a long time to decide his house, Harry spilled everything but his tea.

'Then it put me in Gryffindor instead,' he finished, leaning back in the armchair.

Lily was very quiet.

Harry glanced at the orange sunset, shifting uncomfortably until he couldn't avoid her stern gaze any longer. And there it was, as fierce and undeniable as he'd feared – disappointment.

'Harry, this is exactly what creates and feeds unhealthy house rivalry,' Lily admonished. 'Your father, as you well know, is a Slytherin. Years ago, he showed me a particular form of bravery I've not known any Gryffindor to have – and you exist from that bravery.'

Harry ducked his head, wishing she'd yell at him instead. Disappointment wasn't a slap to the face, but a heaviness making him regret every thought and action that possibly led to it. Her words burned his happy memory of being sorted into Gryffindor, as Harry realised he'd made a judgemental mistake.

'So the hat was right; I should be in Slytherin?' he mumbled miserably, flinching back as she walked to crouch in front of him.

'If you don't also belong in Gryffindor, the hat wouldn't have placed you there.' Lily rested a hand on his. 'You are my son and I'm proud you're in Gryffindor too, but never forget that you're also your father's son. A Slytherin can be just as loyal and brave and true, as any member of the four houses. He was my best friend.'

Lily handed him a photograph. Staring at it, Harry wanted to bury his shame under layers of blankets. Lily and Severus were about his age, laughing together in the Hogwarts library, stacks of books to either side like walls of a fort. It was a magical photo, so they moved and smiled – capturing a moment when his parents were just students like him.

Harry wanted to ask questions, but couldn't find the words.

He should've known better; the Dursleys told their neighbours how naughty and horrible Harry was so no one would talk to him or believe anything he said. Had Severus endured the same ill-reputation when he was a student; did people believe he was bad for being sorted into Slytherin? Lily hadn't - the evidence was in his hands

He couldn't be mad at Ron, as his friend hadn't known, but Harry wouldn't make that mistake again. No one stood up for him at Privet Drive. Malfoy was rude and reminded him of Dudley, but Harry wanted to show his mum he understood. Lily complimented Draco on his loyalty and determination during the scenario task; even Malfoy wasn't all bad.

Harry wanted to teach people the truth – and show his dad he believed in him, not the lies. If he was as much a Slytherin as a Gryffindor, Harry needed to understand both sides of himself. As if knowing his thoughts and determination, Lilly smiled at her son.

'Good boy,' she said, standing. 'I'm proud of you, for having an open mind. You can keep the picture; I want you to have it. Now, it's getting late. I've copied your schedule and will sort out a room for you in my quarters. We'll have lunch here on Sunday.'

Harry nodded, surprised when she embraced him without any anger or disappointment. He exhaled relief, holding his mum tighter. She kissed his forehead, and waved him off.

As Harry left, Lily looked through the tall window at the sun-kissed castle beyond. She knew Severus better than anyone - testing Harry was only part of his intention. For a moment, in his own way, he'd reached out to the boy. No one was supposed to figure it out, not even Harry, but Lily spoke Severus' language.

'I bitterly regret Lily's death,' she deciphered quietly, sadness choking her heart. 'Oh, Severus. I should've known you'd blame yourself.'