From Longman Dictionary of Contemporary Englishfall into stepfall into stepa) WALKto start to walk next to someone else, at the same speed as themfall into step beside/with Holly slowed her pace and fell into step with the old man. b) START DOING somethingto start doing something in the same way as the other members of a groupfall into step with The other countries on the Council are expected to fall into step with the US. → fall
Examples from the Corpus
fall with• Once again, Blue falls into step with Black, perhaps even more harmoniously than before.• The great horse Koulash galloped forward to join the Tsar's horses, and fell into step with them. 