you can gain temporary access to any spell through song. As a bonus action, you can choose any one spell you know exists of a spell level you have spell slots for. Until the end of your current turn, you can cast it as normal using a spell slot. It counts as a bard spell for you. If the spell has a casting time longer than an action, you must begin casting the spell before the end of your current turn, but can continue and complete the spellcasting after the end of of your turn. You can use this ability only once, and regain the ability when you finish a long rest.