What happened to Boo in Fleabag? Fleabag blames herself for the death — and she's right to

Boo (Jenny Rainsford), Fleabag's best friend and her partner in their London guinea pig café, is already dead when Fleabag begins. The first episode, which aired on BBC Three on July 21, 2016, explains that she "accidentally killed herself" while trying to fake a suicide to get back at her boyfriend, who had cheated on her, per Wikipedia's episode summary. The sixth and final episode of series 1 reveals the rest: the woman he cheated with was Fleabag.

Phoebe Waller-Bridge built the story out of her own fear. She told NPR in 2016 that the show grew from looking at the things she loved and imagining losing them, starting with her best friend.

"My biggest fear was what would happen if I lost her now."

— Phoebe Waller-Bridge, to NPR, on her real-life best friend

How Boo died

The details come out in pieces over the first series:

• The plan: After learning her boyfriend cheated, Boo decided to get just hurt enough to end up in hospital so he'd feel guilty, per Distractify. In a flashback, she says she'll get tangled up in a bike.
• The accident: She stepped into a bike lane on a busy road. The crash killed three people, Boo among them. Fleabag calls it an "accidental suicide."
• The secret: Episode 6 shows in flashback that Fleabag slept with Boo's boyfriend.

The café carries the rest of the memory. Hilary, the guinea pig behind its whole theme, was Fleabag's last-minute birthday present to Boo, per Den of Geek.

Why Fleabag blames herself

For five episodes, Fleabag talks straight to the camera about sex, her family and her failing café, and never mentions the one thing she's actually carrying. The audience she's been confiding in finds out last.

When she finally breaks, it's on the walk to the café. She thinks about stepping into traffic herself, and the bank manager (Hugh Dennis) from her loan interview finds her and asks if she's okay. She confesses. He restarts the interview and tells her people make mistakes.

"That's why they put erasers on the ends of pencils."

— the bank manager, to Fleabag, in the series 1 finale

Why she's right to

Boo's death was an accident, and the plan was Boo's own. But the plan only existed because of a betrayal, and Fleabag was half of it. Boo meant to put guilt on the person who cheated on her. Fleabag was one of the two people who did the cheating, so the guilt landed exactly where Boo was aiming it.

Don't miss: Who is Zeke's mother in Gangs of London? One photo in his flat told Ed Dumani everything

The show doesn't argue with that, and neither does Waller-Bridge. She told the A.V. Club in 2016 that she didn't know at first she wanted to kill Boo, "but the intention is that it was meant to be true."

Previously we wrote: Slow Horses made Jack Lowden TV's most lovable failed spy. That's why he'd be a better Bond

The bank manager's line doesn't clear Fleabag either. It tells her she made a mistake, which is forgiveness, and forgiveness only works on someone who's guilty.

Fleabag spends a whole series joking to the camera so we won't look at the one thing she can't say. When she finally says it, the show hands her a pencil eraser, not an alibi.