Marilla unexpectedly adopts the orphaned twins Dora and Davy Keith after the death of their parents. While Dora is well-behaved and obedient, the lively Davy poses educational challenges for Anne: he puts a caterpillar down a classmate's neck, lets Dora fall into a pigsty, and hides a toad in Marilla's bed. Anne uses her model student Paul Irving as an example to motivate Davy to better behavior.

The crisis escalates when Davy locks his sister in Mr. Harrison's shed and lies to trigger a "fun" chase. After a dramatic search, Anne finds the frightened Dora. When Davy sees Anne's tears, he sincerely regrets his actions – especially the lie, which he ignorantly believed to be harmless. Anne explains to him the moral consequences of false statements and forgives him on the condition that he never does it again.

In parallel, Anne reflects on her own tumultuous childhood at Green Gables and realizes that she loves those most who need her guidance – an insight Matthew once had about her. The episode ends with Anne's decision to give the twins the same patient support she herself once received.