Ōtani Yoshitsugu has often been plagued with bad luck, often spending her evenings alone searching for four-leaved clovers, believing in the words of a book written by someone named Angel. One day, Yoshitsugu finds a four-leaved clover and becomes delighted, only to find her luck hasn’t improved at all. Dismayed, Yoshitsugu puts the clover she found in an envelope addressed to Angel and resides herself to her bad luck. To her surprise, she receives a response from Angel, telling her how bad luck can often lead to good luck. The two soon become pen pals, telling each other about their random bouts of good luck and sending each other little gifts. Yoshitsugu saves her money so she can take a trip to see Angel, but loses it whilst helping an old woman who was having a heart attack. As Yoshitsugu becomes frustrated when she stops receiving replies from Angel, she receives a plane ticket from Angel, asking her to come see her. However, when Yoshitsugu arrives, she learns that Angel had passed away from overwork, leaving behind one final letter explaining how Yoshitsugu’s letter stopped her from killing herself and how she looked forward to their meeting.