Senior year should bring fun, friends, and happiness. Not portals, treachery, and murder. Seventeen-year-old Mia Taylor, gatekeeper to an interdimensional portal, wants nothing more than to heal from her romance gone wrong. Illegally falling for her co-worker Regulus had been a huge mistake. But when Regulus goes rogue to hunt down a murderer, Mia must forget her broken heart and use her unique abilities to save him. Traveling across dimensions, she enters a strange and hostile world where a rebel faction holds the key to their escape. Her gift of synesthesia is in high demand, and a secret organization of the otherworldly kind has her in their sights. But sabotage and murder may be the least of her worries. Her ex-boyfriend wants a relationship. Her dad wants her to act normal. Her friends want her to stop moping. Who knew faking happy would be the easiest part of senior year?