Avery and Sadie’s matching tattoos are infinity symbols, although Avery’s is broken, with curves that do not fully connect back to the other lines. If a completed infinity symbol represents eternity, fulfillment, and balance, then Avery’s broken infinity signifies her feelings of being incomplete. It also captures one of her prevailing philosophies on life: “Nothing lasts forever. Everything is temporary. You and me and this” (231). Ironically, the broken tattoo is permanent—even if everything else is temporary, the mark will last. Connor remarks that it looks more like an “S” than an infinity sign, suggesting that Avery branded herself with Sadie’s initial as a permanent sign that she belongs to Sadie and is not truly her own person. It is not until the novel’s end, when Avery publicly reveals the truth about Sadie’s death, that she is able to find fulfillment, feel complete, and move forward with her life. Her grief was temporary, but what she learned from it will last forever.

Literal darkness occurs suddenly and unexpectedly in the novel, from Avery coming home to find the power out to the startling grid overload at the Plus-One Party. In a more figurative sense, being in the dark means one is unaware or deliberately excluded from certain knowledge.