```python
from langchain.chat_models import ChatOpenAI
from langchain.chains import LLMChain, SequentialChain
from langchain.memory import ConversationBufferMemory
from langchain.prompts import PromptTemplate

llm = ChatOpenAI(temperature=0.7,)
memory = ConversationBufferMemory(memory_key="chat_history", input_key="human_input")

system_template = """You are a writer who is well-versed in the writing styles of children's book and story authors.

{chat_history}
Human: {human_input}
Writer:"""
system_prompt = PromptTemplate(input_variables=["chat_history", "human_input"], template=system_template)

author_template = """Given an author's name, describe the writing style of the given author.

Author: {author}

Writer: This is a description of the style of the above author:"""
author_prompt = PromptTemplate(input_variables=["author"], template=author_template)
author_chain = LLMChain(llm=llm, prompt=author_prompt, output_key="author_style")

outline_template = """Given an author's name, a description of their writing style, and a child's age, write an outline for an age-appropriate bedtime story in the style of the given author.

Age: {age}
Author: {author}
Author's Style: {author_style}

Writer: This is an outline for a story in the style of the above author:"""
outline_prompt = PromptTemplate(
    input_variables=["age", "author", "author_style"], template=outline_template
)
outline_chain = LLMChain(llm=llm, prompt=outline_prompt, output_key="outline")

story_template = """Given an outline for a children's bedtime story, write an age-appropriate story in the style of the given author.

Age: {age}
Author: {author}
Author's Style: {author_style}
Story Outline: {outline}

Writer: This is an age-appropriate story (for {age} year-olds), based on the above outline, in the style of {author}:"""
story_prompt = PromptTemplate(
    input_variables=["age", "author", "author_style", "outline"],
    template=story_template,
)
story_chain = LLMChain(llm=llm, prompt=story_prompt)

overall_chain = SequentialChain(
    chains=[author_chain, outline_chain, story_chain],
    input_variables=["age", "author"],
    verbose=True,
    memory=memory,
)
review = overall_chain({"age": 6, "author": "Dr. Seuss"})

print(review)
```