The continuation task, which involves reading an unfinished story and completing its ending, offers good potential for language learning. To enhance students' story‐ending writing abilities, this study proposes two types of concept mapping strategies: group filling‐in‐the‐blanks of a teacher‐constructed guided map and group concept mapping, both of which are meant to help students clarify storylines by visualizing a story onto a concept map. A quasi‐experiment was conducted in three classes. Students in Class 1 collaboratively filled in the blanks on a concept map and then wrote completions to three stories. In Class 2, students collaboratively constructed their own concept map and then wrote completions to the same stories. Class 3 students collaboratively wrote completions to the same stories without any concept mapping. Students’ story completions, diaries, responses to questionnaires, the researcher's observation notes, and teacher interviews were collected and analyzed using ANOVAs (Analysis of variance), paired‐sample t‐tests and thematic and domain analysis. The results showed that concept mapping strategies assisted students’ story‐ending writing quality with students achieving higher scores when using the group concept mapping strategy compared to those not using any mapping strategies. Nine interactive patterns were identified, with the collaborative pattern dominating, and these patterns evolved dynamically as the co‐continuation tasks proceeded. Overall, both students and teachers perceived the proposed strategies positively.