This lesson plan teaches students about plural nouns. It provides definitions of singular and plural nouns. There are three main rules for changing nouns to plural: adding 's', adding 'es' for words ending in s, x, z, o, ch, sh, and replacing 'y' with 'ies' for words ending in 'y' preceded by a consonant. The lesson includes warm-up activities like adding 's' to sample nouns, and two main activities that involve students writing plural forms of sample nouns in sentences and as standalone words. The lesson concludes with an assessment and follow-up activity having students discuss plural body parts.