Memories in the Pensieve show Harry the true story of Snape’s life and love

After Snape dies in the Shrieking Shack (DH32), Harry takes the vial of his important memories to Dumbledore’s empty office and pours them into the Pensieve. Snape’s early childhood remembrances appear before him – starting in 1969, the first meeting of the lonely, ragamuffin-like boy at age nine with Harry’s mother Lily and ordinary Aunt Petunia  on the playground in Cokeworth; the blossoming friendship of the two magical children to the exclusion of the upset Petunia; and the first train-ride aboard the Hogwarts Express in 1971, where the Half-Blood Severus and Muggleborn Lily first encounter pure-bloods Sirius Black and James Potter. Snape’s fondest wish is that he and Lily will both be put into Slytherin, which he believes is a house for “brains over brawn” while James tells him he wants to be in Gryffindor for the “brave of heart” (DH33). But when Harry views Snape’s Sorting Hat memory, the boy joins Lucius Malfoy at the Slytherin table, while Lily is placed into Gryffindor with Sirius and James.

Fast forwarding to their early teens, the memories show the growing rivalry between James and his friends (known as The Marauders) and Snape, who is a victim of their bullying and thus suspicious of their relationship with Remus Lupin, whom the young Snape realizes may be a werewolf. While he tries to warn Lily to be wary of the group out of both concern and jealousy of James, she is more concerned with Snape’s growing fascination with Dark Magic. When the memory of O.W.L. exam days starts unfolding, Harry realizes he has seen watched it once before when he was taking Occlumency Lessons from Snape (OP28), so he hangs back from the action as James and Sirius torment Snape while Lily tries to help her friend only to be called the “unforgivable word” Mudblood. Although Snape comes to the entrance of Gryffindor House that night to beg forgiveness, the break between Snape and Lily is irreparable at that point, and Lily refuses to accept his apology.

The next set of memories begins on a Windy hilltop sometime in 1980, with an emotionally distraught  Snape, now a Death Eater in thrall to Voldemort, telling Dumbledore that he overheard Trelawney’s prophecy about a child who could defeat the Dark Lord and gave it to his Master. Voldemort’s interpretation meant that he was surely going to attack the Potters and their baby, and while Snape had begged him to spare Lily’s life, he was hedging his bets in seeking assurances from Dumbledore that Lily especially could be protected. The Headmaster is disgusted with Snape and asks him what he is willing to do in return for the safety of all the Potters, not just Lily. Snape replies “Anything.” The next memory shows Snape in Dumbledore’s office, sobbing “like a wounded animal” due to the deaths of the Potters, who were double-crossed and sold-out by Peter Pettigrew, although both Snape and Dumbledore believe at the time it was Sirius Black (PA19). At the vulnerable moment of Snape’s worst grief over the dead Lily when he is nearly suicidal, Dumbledore rather manipulatively extracts his promise to keep protecting Lily’s child, Harry, for years to come in case the Dark Lord ever returns. Snape agrees but makes Dumbledore swear never to tell anyone of his unrequited love for Lily.

The third set of memories begins during Harry’s first year at Hogwarts in 1991, as now-Potions Master Snape expresses his opinion to Dumbledore that the boy is arrogant just like his father James. Dumbledore brushes that aside, telling Snape to keep an eye on Professor Quirrell, who was later exposed to be possessed by Lord Voldemort (PS17). Harry views Snape and Dumbledore talking at the Yule Ball in his fourth year, 1994, discussing the return of Dark Marks to the arms of Death Eaters such as himself and Igor Karkaroff, who wants to flee before the Dark Lord rises again. Dumbledore suggests that because Snape is the braver man, he was perhaps sorted “too soon” into Slytherin, implying he should have been Gryffindor with Lily. Harry views Snape’s “stricken” look at the idea. The memories jump a few years more to the night in 1996 when Dumbledore returned to Hogwarts after putting on Marvolo Gaunt’s ring which was set with the Resurrection Stone, and which had been turned into a Horcrux by Lord Voldemort. Dumbledore does not tell Snape that he put it on hoping to summon his dead sister and mother, although Dumbledore’s spirit form explains that to Harry in his vision of King’s Cross Station (DH35). While Dumbledore thanks Snape for saving his life by trapping the curse in the blackened hand for one year, he also tells him the bad news that if Draco Malfoy is unable to kill him in the future, then Snape must do it himself. In the memory, a shocked Snape is reluctant to agree, worrying about damage to his soul, and unwilling to kill the Headmaster. Dumbledore convinces him to agree by explaining he doesn’t want to give the Death Eaters a chance to defile his body.

Then comes a series of important memories as Dumbledore explains his plans to defeat Voldemort even after his death, telling Snape to notice when Nagini seems to have extra protection, which Harry saw previously when the snake attacked and killed Snape from inside a glowing bubble (DH32). Dumbledore reveals to Snape the bombshell fact that Harry is connected to Voldemort through a fragment of his soul embedded in Harry’s scar, and that in order for the Dark Lord to be defeated again, Harry will have to die. Overwhelmed and furious, Snape laments that Dumbledore has used him all through the years to protect Harry, only to see him led “like a pig for slaughter.” When Dumbledore wonders if Snape is expressing love for Harry, Snape produces his Patronus instead, the silver doe which represents his love for Lily. Dumbledore seems surprised and wonders “After all these years?” to which Snape replies, “Always.”

The last memories show the aftermath of Dumbledore’s death on the Astronomy Tower – Snape in the Headmaster’s Office with Dumbledore’s portrait discussing plans for the Battle of the Seven Potters; Snape in battle attempting to save the lives of Lupin and George Weasley but accidentally cutting off George’s ear with Sectumsempra; then Snape in Sirius Black’s old bedroom at Grimmauld Place, weeping over a letter and photograph of the Potter family,  which Harry also found (DH10) after Snape ripped James from the picture, and took the signature “Love, Lily” from the letter (DH10). The last two memories are of Snape finding out from the portrait of Phineas Nigellus the location where Harry and Hermione were hiding in the Forest of Dean. Phineas uses the term “Mudblood” for Hermione and Snape chastises him, showing how much he has changed since ruining his friendship with Lily over the same word. Harry watches as Snape swings open the portrait of Dumbledore to reveal the hidden Sword of Gryffindor, which Harry now knows he left in the forest pool for he and Ron to find so they could destroy Slytherin’s locket Horcrux (DH19), led to the pool by the silver doe patronus which Harry also now knows represents the love Snape always had for his mother, Lily.

Timeline Notes

It is almost 4:00 AM and still dark outside when Harry finishes watching Snape's memories in the Pensieve and leaves the castle to go to the Forest (DH34).